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DEPARTMENT OF MEDICAL IMAGING, UNIVERSITY OF TORONTOANNUAL RESEARCH DAY <strong>2009</strong>Date: Thursday, April 16, <strong>2009</strong>Location: Ben Sadowski Auditorium, 18th floor, Mount Sinai Hospital, 600 University Avenue9:00 am Patrice Bret IntroductionChest and Cardiac <strong>Imaging</strong>Session Chair: Narinder Paul9:08 am Susan James Apical hypertrophic cardiomyopathy: When is it benign disease?Correlating MRI findings with clinical outcome9:16 am Robert Kurtz Coronary CT angiography following myocardial perfusion scintigraphy inpatients with low to intermediate risk <strong>of</strong> coronary artery disease:Determination <strong>of</strong> predictive variables9:24 am Narinder Paul Optimal p<strong>has</strong>e reconstruction <strong>of</strong> coronary artery segments: The CORE 64experience9:32 am Ida Chan Reliability <strong>of</strong> human and computer automated analysis for tracheomalacia:A comparison9:40 am Perry Choi Pulmonary high resolution CT findings and CFTR gene mutations inpatients with chronic sinopulmonary disease9:48 am Monika Dhopeshwarkar Screen detected lung cancer: A retrospective analysis <strong>of</strong> CT appearance9:56 am Zhi Dong Detection <strong>of</strong> pleural plaques with low-dose computed tomography(LDCT) in asbestos workers10:04 am Alexander McGregor Analysis <strong>of</strong> gender differences in emphysema development in smokers10:12 am Ravi Menezes Changes in smoking habits in participants <strong>of</strong> a lung cancer screeningstudy10:20 am Babak Shamshirsaz Lesions after stereotactic body radiotherapy: Misdiagnoses and pitfalls10:28 am Dennis Boparai Incidental lumbar spine pathology detected on pre-uterine arteryembolization MRIs10:36 am COFFEE BREAKBreast, MSK and PhysicsSession Chair: Marshall Sussman10:48 am Leah Shuparski Merits <strong>of</strong> five clinical dosimeters in an interventional radiology setting10:56 am Pavel Crystal MRI-guided vacuum-assisted breast biopsy: Initial experience11:04 am Riham Eiada Can DWI be a noninvasive method to predict axillary metastases inpatients with biopsy proven breast carcinoma?11:12 am Arifa Sadaf Potential contribution <strong>of</strong> computer-aided detection to the sensitivity <strong>of</strong>full-field digital mammography11:20 am Afsaneh Amirabadi Assessment <strong>of</strong> early synovium and cartilage changes in hemophilicarthropathy in a rabbit model11:28 am Sam Dabbo An audit <strong>of</strong> bone mineral density reporting11:36 am Ueli Studler Feasibility study <strong>of</strong> simultaneous physical and real-time MRI examination<strong>of</strong> medial collateral ligament injuries in a 1.5-T wide-bore magnet1 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>11:44 am Andrea Doria MR imaging as a screening tool for early detection <strong>of</strong> intraarticular bleedin hemophilic children: A systematic review11:52 am April Khademi Automatic contrast enhancement <strong>of</strong> cerebral white matter lesions inFLAIR MRI12:00 pm Marshall Sussman A post-processing method for generating arbitrary T2-weighted contrast inMRI12:08 pm LUNCHNeuroimagingSession Chair: David Mikulis1:12 pm Daniel Baxter Comparison <strong>of</strong> Gad<strong>of</strong>osveset trisodium (Vasovist) steady state enhancedmagnetic resonance angiography (MRA) with first pass and threedimensional time <strong>of</strong> flight MRA at 1.5 Tesla in the follow-up <strong>of</strong> coiledcerebral aneurysms1:20 pm Fang Liu Sex differences in the human corpus callosum microstructure: T2 myelinwaterimaging versus diffusion tensor imaging1:28 pm David Mikulis Exhausted cerebral autoregulation is spatially associated with corticalatrophy1:36 pm Vitaly Sygal Comparative detectability <strong>of</strong> magnetic susceptibility signals seen on EPI-GRE, MPGR and VEN BOLD sequences using 3T MRI: Preliminaryresults1:44 pm Bejoy Thomas Assessment <strong>of</strong> cerebrovascular reactivity using real time BOLD MRI inchildren with Moyamoya disease: A feasibility study1:52 pm Rebecca Thornhill Dynamic susceptibility contrast MRI in acute ischemic stroke: Surrogatemeasures <strong>of</strong> BBB permeability for the prediction <strong>of</strong> hemorrhagictransformation2:00 pm Jean Marie U-King-Im Characterization <strong>of</strong> carotid plaque hemorrhage: A CT angiography andMR direct thrombus imaging study2:08 pm Jeff Winter DTI and cerebrovascular reactivity MR imaging in the developing swinebrain2:16 pm Johanna Monsalve <strong>Imaging</strong> features <strong>of</strong> anterior pyriform aperture stenosis and centralincisor syndrome including labyrinthine dysplasia2:24 pm Aditya Bharatha MR imaging assessment <strong>of</strong> parapharyngeal extension in nasopharyngealcarcinoma2:32 pm COFFEE BREAKVascular and Interventional <strong>Imaging</strong>Session Chair: Dheeraj Rajan2:42 pm Rob Beecr<strong>of</strong>t Short-term outcomes after varicocele repair by embolization andmicrosurgical varicocelectomy: Implications for IVF planning2:50 pm Mark Baerlocher Interim results <strong>of</strong> the Celect IVC filter registry2:58 pm Clare Bent Incidence <strong>of</strong> type one endoleak in patients with a hostile neck using suprarenal fixation aortic stent grafts: Are the instructions for use (IFU) stillapplicable?2 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>3:06 pm Del Dhanoa Assessment <strong>of</strong> clinical predictors for endoleaks and complications inpatients undergoing endovascular aneurysm repair (EVAR)3:14 pm Donna D’Souza Combined prophylactic internal iliac artery balloon occlusion and uterineartery embolization in the management <strong>of</strong> invasive placenta3:22 pm Kiat T. Tan Molecular imaging <strong>of</strong> atherosclerotic plaque3:30 pm John Kachura Radi<strong>of</strong>requency ablation <strong>of</strong> renal cell carcinoma: Mid-term results3:38 pm Kebby King Bland hepatic artery embolization for symptomatic neuroendocrine tumormetastases: An 11-year experience3:46 pm Dheeraj Rajan Efficacy <strong>of</strong> stent-graft placement for salvage <strong>of</strong> dysfunctionalhemodialysis fistulas3:54 pm Ahmed Farooq Retrospective review <strong>of</strong> non-vascular findings in peripheral CTangiography4:02 pm Joe Barfett Limb perfusion: Characterization <strong>of</strong> a new techniqueAbdominal, GU, GI <strong>Imaging</strong>Session Chair: Martin O’Malley4:10 pm Martin O’Malley CT urography: Image quality and accuracy for upper tract urothelialcancer4:18 pm Mostafa Atri Microbubble DCE-US, DCE-CT, and DCE-MRI for the assessment <strong>of</strong>tumor response to Sunitinib treatment <strong>of</strong> renal cell carcinoma: Preliminaryresults4:26 pm David Kelton Radiology resident on-call productivity during a night shift schedule: Apilot project4:34 pm Sean McSweeney Biliary anatomy <strong>of</strong> potential donor for living donor liver transplantation:The utility <strong>of</strong> CT cholangiography in cases with indeterminate results onMRCP4:42 pm Richa Mittal The impact in abdominal imaging with the introduction <strong>of</strong> a dedicatedemergency CT4:50 pm Hojun Yu Pseudoenhancement within local ablation zone <strong>of</strong> hepatic tumors due tononlinear artifact on contrast-enhanced ultrasound4:58 pm Aiden Moktassi Magnetic resonance imaging <strong>of</strong> liver disease in hereditary hemorrhagictelangiectasia5:06 pm Jaydeep Halankar Interval growth <strong>of</strong> focal nodular hyperplasia in the liver on MR imaging5:14 pm Paula O’Donoghue No significant difference between nuchal translucency (NT) in weeks 11-13 +6 <strong>of</strong> singleton pregnancies conceived spontaneously and by IVF/ICSI5:22 pm Patrice Bret Closing Remarks<strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong><strong>has</strong> <strong>been</strong> <strong>made</strong> possible bythe generous support <strong>of</strong> GE Healthcare.3 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Chest and Cardiac <strong>Imaging</strong>4 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Apical hypertrophic cardiomyopathy: When is it benign disease?Susan James, Elsie Nguyen, Visal Pen, Yon Mi Sung, Patrick Sparrow, Naeem Merchant<strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong>, University <strong>of</strong> TorontoPurpose: Apical hypertrophic cardiomyopathy (ApHCM) is a rare morphologicalsubtype <strong>of</strong> HCM thought to have a benign course but recent literature <strong>has</strong> challenged this.The purpose <strong>of</strong> our study was to describe the most common imaging findings <strong>of</strong> ApHCMand to correlate with clinical outcome.Methods and Materials: Retrospective review <strong>of</strong> MRIs for 30 ApHCM patients (22men, mean age 52 yrs, range 18-81 yrs) by two radiologists blinded to patient clinicaloutcome. Disagreements were resolved by consensus. MR imaging features such asmaximum wall thickness, presence and extent <strong>of</strong> delayed enhancement, right ventricularinvolvement, left atrial size, apical aneurysms, left ventricular mass and function wererecorded. Clinical outcome measures such as arrhythmia, myocardial infarction, stroke,heart failure and syncope were recorded. Fisher’s exact test was used for categoricalvariables and t-test used for continuous variables to compare MRI findings among thesymptomatic and asymptomatic groups.Results: Atrial fibrillation or flutter (n=3), stroke (n=3) and non-sustained ventriculartachycardia (n=2) were the most common events seen in 27% <strong>of</strong> patients (8/30) who wereolder than the asymptomatic group (mean 62 yrs vs. 49, p
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Coronary CT angiography following myocardial perfusion scintigraphyin patients with low to intermediate risk <strong>of</strong> coronary artery disease:Determination <strong>of</strong> predictive variablesR Kurtz, V Prabhudesai, D Marcuzzi, P McEwan, J Sloninko, G Tomlinson, M FreemanPurpose: To determine the clinical and scintigraphic variables that predict the presence<strong>of</strong> significant coronary artery disease (CAD) by Coronary computed tomographyangiography (CCTA) in those patients with low-to-intermediate risk for CAD followingMyocardial Perfusion <strong>Imaging</strong> (MPI).Materials and Methods: This study was approved by the local research ethics board.Informed consent was waived. A retrospective analysis was performed on 968consecutive patients who underwent CCTA at our institution in a two-year period (2006-2008). We identified 163 patients with low-to-intermediate risk for CAD (according toage, symptoms, no prior cardiac event, results <strong>of</strong> stress testing and MPI) who also hadMPI within 12 months <strong>of</strong> CCTA. CCTA grading <strong>of</strong> coronary artery stenoses wasperformed and those patients with a stenosis <strong>of</strong> at least 50% in at least one vessel weredefined as having significant CAD. We performed univariate analyses <strong>of</strong> age, gender,body mass index (BMI), coronary risk factors (diabetes mellitus, hypertension, smoking,hypercholesterolemia, family history), presenting symptoms (angina, atypical angina,nonanginal chest pain, asymptomatic), exercise induced ST depression and perfusionimaging for the prediction <strong>of</strong> significant CAD by CCTA. Multiple logistic regression wasused to assess the dependence <strong>of</strong> significant CAD on patient age, gender, number <strong>of</strong> riskfactors and MPI results.Results: Increased age (p=0.0002), hypertension (p=0.0373), and hyperlipidemia(p=0.0012) were associated with significant CAD on CCTA. Increased number <strong>of</strong> riskfactors were present in those with significant CAD on CCTA (p=0.0036). Typical anginawas a more frequent clinical presentation while atypical and non-anginal chest pain was aless frequent clinical presentation in those with significant CAD on CCTA (p=0.03).Those patients with reversible perfusion defects, with and without positive stress testwere most predictive <strong>of</strong> significant CAD with likelihood ratios <strong>of</strong> 5.48 and 1.92,respectively. There was a statistically significant association between overall MPI resultand significant CAD on CCTA (p=0.002). Age (OR=2.13; p=0.0003), number <strong>of</strong> riskfactors (OR=1.58; p=0.015) and MPI results (OR=3.01; p=0.0092) were all found to beassociated with significant CAD in multiple logistic regression.Conclusion: The presence <strong>of</strong> significant CAD as determined by CCTA is associated withdemographic factors, type <strong>of</strong> clinical presentation and results <strong>of</strong> MPI. The presence <strong>of</strong>reversible perfusion abnormalities is a strong independent predictor <strong>of</strong> significant disease.6 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Optimal p<strong>has</strong>e reconstruction <strong>of</strong> coronary artery segments:The CORE 64 experienceNS Paul, A Zadeh, A Vavere, I Gottlieb, J Hoe, J Brinker, M Dewey,J Miller, M Clouse, C Rochitte, E Shapiro, H Niinuma, J AC LimaPurpose: To assess the feasibility <strong>of</strong> using prospective EKG gating with 64 row MDCTin CT coronary angiography (CTCA), by analysing the optimal p<strong>has</strong>e reconstructionsused in retrospectively gated acquisitions during the CORE 64 trial.Method and Materials: 9 cardiac centres recruited 401 patients to have CTCA andcoronary angiography from Oct 2005-Jan 2007 (CORE 64 Trial). CTCA was performedon 64 row MDCT (Aquilion, Toshiba, Japan), targeting a heart rate (HR) less than orequal to 65 bpm.Raw data were analysed by a central core lab to determine the optimal p<strong>has</strong>e <strong>of</strong>reconstruction for motionless coronary artery segments (CAS) using a 15 segment model.Image analysis was performed by 2 blinded, independent readers. Readers could usevolume rendered images, curved MPR's, MIPs, and cross-sectional images. A singlep<strong>has</strong>e <strong>of</strong> reconstruction (SPR) was recorded when both readers agreed that a singleacquistion window was optimal for all CAS. In all other scenarios, more than one p<strong>has</strong>ewas recorded.Results: To date, 291 patient datasets have <strong>been</strong> analyzed; 214 men (73%), mean age59y (40-89) totaling 5529 segments. On a per patient basis, overall 70% <strong>of</strong> patientsrequired a single p<strong>has</strong>e for optimal CTCA reconstruction, on a per segment basis, 5064segments (91.6%) were optimally reconstructed using a single p<strong>has</strong>e (SPR) for the entireexam.SPR as follows: HR (no. <strong>of</strong> patients, % SPR) per patient analysis; 70 (18, 53%). Per segment analysis: HR(no. <strong>of</strong> segments, %SPR); 70 (646, 88%).HR determined the optimal p<strong>has</strong>e for SPR as follows: HR (mean p<strong>has</strong>e in ms, 2SD, min,max); 70 (574.6, 159.4,140, 940).Conclusion: 1. At lower heart rates, there is increased likelihood <strong>of</strong> using a single p<strong>has</strong>efor optimal reconstruction (SPR) <strong>of</strong> coronary artery segments using conventional 64 rowMDCT. 2. At heart rates below 55bpm, a SPR is used in 84% <strong>of</strong> patients. 3. Withincreasing heart rate, the optimal p<strong>has</strong>e <strong>of</strong> reconstruction shifts from the diastolic towardsthe systolic p<strong>has</strong>e <strong>of</strong> the cardiac cycle.Clinical Relevance/Application: Prospective EKG gated cardiac CT is a feasibleproposition. To optimize radiation dose reduction, the heart rate needs to be aggressivelycontrolled, ideally to 55bpm or less.7 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Reliability <strong>of</strong> human and computer automated analysisfor tracheomalacia: A comparisonIda H Chan, <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong>, University <strong>of</strong> TorontoSheldon Mintz, Women’s College Hospital, University <strong>of</strong> TorontoMartin Shoichet, Faculty <strong>of</strong> Medicine, University <strong>of</strong> TorontoEric Stutz, Faculty <strong>of</strong> Medicine, University <strong>of</strong> TorontoDavid A K<strong>of</strong>f, Sunnybrook Health Sciences Centre, University <strong>of</strong> TorontoPurpose: Comparing the reliability <strong>of</strong> human and computer automated analysis fortracheomalacia.Materials and Methods: CTs from 18 subjects from a previous tracheomalaciasurveillance study were randomly selected for analysis, 8 meeting standardizeddiagnostic criteria for tracheomalacia as measured by one human observer. Each subjecthad a helical inspiratory MDCT, end inspiratory and expiratory HRCT, and a low dosedynamic expiratory scan. Tracheomalacia was defined as a >50% decrease in trachealcross-sectional area comparing dynamic expiratory to helical scans at the clavicular head(CH) and aortic arch (AA). A human observer then independently re-analyzed theoriginal CTs, and a custom ImageJ plugin (IJ) that automatically segmented andcalculated tracheal cross-sectional area. Ratios comparing expiratory and inspiratoryHRCTs (EI) as well as the forced-expiratory to helical (FH) scans were calculated.Results: The first human observer identified 8/18 participants with tracheomalacia;independent observer 7/18; IJ 7/18. IJ repeat analysis on the same study did not vary.Cohen’s kappa was 0.89 between the two human measurers, and between the computer toaveraged human set. EI ratios did not correlate with FH ratios, and did not predicttracheomalacia as none were less than 50%. The interclass correlation coefficient (ICC)varied from 0.21 to 0.90 between the humans (mean 0.56); and 0.45 to 0.98 between theaveraged human and computer measurers (mean 0.76). For all the EI ratios, there wereno significant differences by paired-t value testing between the groups. FH ratiosdiffered significantly (p
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Pulmonary high resolution CT findings and CFTR gene mutationsin patients with chronic sinopulmonary diseasePerry Choi, <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong>, University <strong>of</strong> TorontoWilliam Weiser, <strong>Department</strong> <strong>of</strong> Radiology, St. Michael’s HospitalTanja Gonska, <strong>Department</strong> <strong>of</strong> Respirology, St. Michael’s HospitalAnnie Dupuis, <strong>Department</strong> <strong>of</strong> Respirology, St. Michael’s HospitalElizabeth Tullis <strong>Department</strong> <strong>of</strong> Respirology, St. Michael’s HospitalPurpose: To determine the relationship between CFTR gene mutations and severity <strong>of</strong>pulmonary CT findings in patients with chronic sinopulmonary disease.Method: Patients with symptoms compatible with chronic sinopulmonary disease wereprospectively recruited. Participating patients underwent medical questionnaire, clinicalassessment, CFTR gene sequencing, pulmonary high resolution CT analysis with theBhalla 1 scoring system, and functional analysis with sweat chloride testing and nasalpotential difference measurements.Results: Eighty-one patients were prospectively recruited. Of those, thirty-sevenpatients had appropriate symptoms to justify completion <strong>of</strong> all diagnostic tests includingCT thorax scan. Subgroup analysis <strong>of</strong> the 37 patients with CT scans revealed a mean age<strong>of</strong> 38 years. Seven <strong>of</strong> the 37 patients (19%) had two mutations, 8 (22%) had onemutation, and 22 (59%) did not have any mutations in the CFTR gene. There was a trendtowards a more severe Bhalla CT score in patients with greater number <strong>of</strong> mutations.Patients with no CFTR mutations had a mean CT score <strong>of</strong> 5.7 (n=22), those with onemutation had a mean CT score <strong>of</strong> 7.1 (n=8), and those with two mutations had a mean CTscore <strong>of</strong> 9.7 2 (n=7). The patients with two CFTR mutations also had sweat chloride andnasal potential difference values compatible with cystic fibrosis. The mean Bhalla CTscore was more severe in patients meeting diagnostic criteria for cystic fibrosis (n=7,19%) compared with those not meeting criteria (Bhalla CT score <strong>of</strong> 10 vs. 6 respectively,p=0.006).Conclusion: There is an increased frequency <strong>of</strong> CFTR gene mutations in patients withchronic sinopulmonary disease. CT studies demonstrated a trend towards more severepulmonary findings in patients with increased number <strong>of</strong> CFTR gene mutations.1Bhalla et al. Radiology. 1991;179:783-788.2A higher value in the CT Bhalla score signifies greater severity <strong>of</strong> pulmonary findings.9 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Screen detected lung cancer: A retrospective analysis <strong>of</strong> CT appearanceMonika Dhopeshwarkar, Heidi Roberts, Ravi Menezes, Zhi Dong,Igor Sitartchouk, Shaf Keshavjee, Scott BoernerObject or Purpose <strong>of</strong> Study: To retrospectively evaluate characteristics <strong>of</strong> cancersdiagnosed in a low dose computed tomography lung cancer screening study.Materials, Methods and Procedures: As part <strong>of</strong> I-ELCAP, we screened a cohort<strong>of</strong> 4738 at risk current and former smokers, 2601 (55%) women and 2137 (45%) men.Seventy-seven (77) cancers in 75 individuals were detected and evaluated for time point<strong>of</strong> detection, location, morphology, histology, stage at diagnosis, treatment and survival.In 37 cases PET was available for correlation. Follow up imaging for computation <strong>of</strong>growth rates was available in 57 cases.Results: 77 cancers were found in 75 individuals, 56 women and19 men, raging in agefrom 50-79 years (mean 63). Only 5 (6.5%) cancers were not seen on baseline scan.Histology revealed 56 (73%) adenocarcinoma, 11 (14%) squamous cell cancer (SCC),5 (6%) small cell lung cancer (SCLC), 2 (3%) large cell carcinoma and 3 (4%) carcinoid.Most common location was LUL (34%) & RUL (31%). 44 cancers were solid (57%),14 (18%) non solid & 19 (25%) part solid. 32 (40%) lung cancers had spiculations and54 (70%) irregular margins. Median tumor size was 17x13 mm.53 (69%) cancers were Stage I (IA51%, IB18%). Most <strong>of</strong> the cancers (n=57, 74%) weretreated surgically. To date 65 patients are alive, with a median observation time <strong>of</strong>26 months, survival is 87%.Of 37 cancers evaluated by PET scan, 20 (54%) were metabolically active: all <strong>of</strong> thesquamous, SCLC and large cell cancers but only 12 (48%) <strong>of</strong> the adenocarcinoma wereactive.Of the 57 cases with follow up CT scans, 34 nodules increased in size. Mean doublingtime (DT) for all cancers was 232 days (median 113). In 26 women, mean DT was239 days (median 131), while in 8 men mean was 110 days (median 87). DT <strong>of</strong> > 400days was present in 5 cases, all women and all adenocarcinoma. The mean and medianDT for adenocarcinoma was 237 and 123 days respectively, for SCLC 136 and 148 daysrespectively, and for SCC 73 and 63 days, respectively.Significance <strong>of</strong> the Conclusions: Screening detects lung cancer in early treatable stage.Women have a higher prevalence <strong>of</strong> lung cancers and have more slow-growingadenocarcinoma. Most cancers can be surgically resected and survival is high after amedium observation time <strong>of</strong> 26 months.10 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Detection <strong>of</strong> pleural plaques with low-dosecomputed tomography (LDCT) in asbestos workersZhi Dong, Demetris Patsios, Monika Dhopeshwarkar,Andre M Pereira, Ravi J Menezes, Heidi RobertsPurpose: The pleural plaque is a specific sign <strong>of</strong> asbestos exposure, and can besensitively revealed with low-dose CT. The purpose <strong>of</strong> this study is to analyze prevalence<strong>of</strong> pleural plaques (PP) in asbestos workers with low-dose CT (LDCT) and itsdemographic correlation.Material and Methods: 802 participants (M: F=790:12; mean age 60.6Y) were asbestosworkers from Early Diagnosis <strong>of</strong> Mesothelioma and Lung Cancer Program. The subjectsmet the enrollment criteria <strong>of</strong> age above 30 years old being in general good health withno prior cancer history; initiating asbestos exposure over 20 years. The smoking packyear(PKY) and asbestos exposure duration (Years) were recorded.All participants underwent full chest CT scan (GE Lightspeed QXi / Plus). The low-dosetechnique was set up at 120 kV, 50~60 mA, and slice thickness was1.25 mm.The CT demonstration <strong>of</strong> PP was recorded by its anatomic location <strong>of</strong> costal,diaphragmatic, mediastinal and fissural pleura. The extent <strong>of</strong> none, mild, moderate andsevere PP were scored as 0~3 respectively, according to the percentage <strong>of</strong> pleural surfaceinvolvement (0, 30%).t-tests for average age and exposure duration between PP+ and PP- groups; Pearson'scorrelation for PP extent with age, PKY and exposure Yrs; Chi-square test for PP+/PPandsmoking/nonsmoking factors were analyzed. The p < 0.05 were considered to besignificant.Results: In this (802) investigated population, the positive PP detected with LDCT was497 (62%) and negative 305 (38%).Of 497 CT positive cases, the mild, moderate and severe PP were 341 (69%), 134 (27%)and 22 (4%) respectively.There was 8 year difference <strong>of</strong> the average age between PP positive (64Y) and negative(56Y) groups (t-test p
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>The PP risk ratio for smoking to non-smoking group was 1.23; while in smokers withPKY >20, the risk ratio was 1.27.In 497 PP cases, the costal pleura was involved in 480 (97%) cases with 28 yrs exposureduration, this prevalence were 1.26 times, 3.2 times and 32 times more frequent thandiaphragmatic (381, 77%, 27.1yrs), mediastinal (150, 30%, 27.5 yrs) and fissural pleura(15, 3%,30.7 yrs) respectively.Conclusion: Aging had a predominant role in the extent <strong>of</strong> PP development. Smoking(>20PKY) increased the risk <strong>of</strong> PP in asbestos workers. Costal pleura were morevulnerable to asbestos related pleural plaques than diaphragmatic, mediastinal, andfissural pleura.12 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Analysis <strong>of</strong> gender differences in emphysema development in smokersAlexander McGregor, George Dong, Ravi Menezes, Heidi RobertsPrincess Margaret Hospital, University Health NetworkPurpose: Data on transgender differences in emphysema is still limited. The purpose <strong>of</strong>this study is to verify whether differences exist in the development <strong>of</strong> emphysematousareas between males and females, and to examine the influence <strong>of</strong> the relationshipbetween emphysema and clinical features.Methods and Materials: We used multi-detector computed tomography (MDCT) scansobtained by the International Early Lung Cancer Action Project (I-ELCAP) for thisretrospective analysis. The MDCT scans were analyzed using an automated emphyse<strong>made</strong>tection program (YACTA version 0.9) which provided data on several quantitativeparameters such as Lung volume (ml), MLD (HU), 15th Percentile point (HU),Emphysema clusters by class (%), and Emphysema type (%). For these parameters,multiple linear regression models were applied to asses the gender effect, after allowancefor age, body mass index (BMI), and smoking history.Results: Females when compared to males showed less extensive development inemphysema cluster classes 1 and 2. Centrilobular emphysema development wassignificantly greater in females over males. Males showed more panlobular emphyse<strong>made</strong>velopment than females.Conclusion: Males and females develop emphysema differently as a result <strong>of</strong> lungdamage caused by tobacco exposure. In smokers with relatively similar exposure, genderinfluences the size <strong>of</strong> the emphysema clusters.13 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Changes in smoking habits in participants <strong>of</strong> a lung cancer screening studyRavi Menezes, Maureen McGregor, Heidi RobertsPurpose: To examine the attitudes towards smoking cessation and health concerns, andto identify predictors <strong>of</strong> change in smoking behaviour in a group <strong>of</strong> smokers enrolled in alung cancer screening study.Methods: Data were analyzed from 950 individuals enrolled in a study that examinedthe ability <strong>of</strong> low dose computed tomography to detect lung cancer at an early stage. Allwere at least 50 years old, current smokers at baseline, and received an annual repeatexamination. Attitudes towards smoking cessation and health concerns were determinedvia a baseline questionnaire. Smoking habits were determined at baseline and annualrepeat screening. The associations between smoking reduction at the annual repeat,baseline LDCT results and questionnaire responses were examined.Results: The most frequent reason provided for participating in the screening study wasconcerns over tobacco use (n=800, 84%), 67% (n=634) <strong>of</strong> the participants reported beingworried about being diagnosed with cancer, and 79% (n=652) reported a desire to quitsmoking during the next six months. At the annual repeat examination, 13% (n=126)reported having abstained from smoking in the previous month, while another 31%(n=293) reduced the amount <strong>of</strong> packs smoked per day. Bivariate and multivariateanalyses revealed that being worried about cancer, seriousness about quitting, and time t<strong>of</strong>irst cigarette were significant predictors <strong>of</strong> smoking cessation (p
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Lesions after stereotactic body radiotherapy: Misdiagnoses and pitfallsBabak A Shamshirsaz MD 1 , Andrea Bezjak MD 2 , Ravi Menezes PhD 1 ,Mojgan Taremi MD 2 , Heidi Roberts MD 11 <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong>, University Health Network2 <strong>Department</strong> <strong>of</strong> Radiation Oncology, Princess Margaret HospitalPurpose: To demonstrate misdiagnoses and pitfalls in interpretation <strong>of</strong> the lesions afterstereotactic body radiotherapy (SBRT) for lung cancer treatment.Materials and Methods: We retrospectively evaluated 4 patients (2 male, 2 female)with Stage T1N0M0 (in one case, T2N0M0) non-small cell lung cancer in LUL (in onecases bi-lateral and in other case in LLL), who were treated with SBRT in PrincessMargaret Hospital. Pre and post SBRT treatment CT-scans <strong>of</strong> the chest have <strong>been</strong>performed in all cases. The CT scans <strong>of</strong> these patients have <strong>been</strong> misinterpreted as tumorrecurrence (except one case as SBRT related changes) and eventually found to betreatment related (in one case tumor recurrence). The CT scans were evaluated for thepresence <strong>of</strong> features differentiating tumor from treatment changes.Results: Follow up CT-scan was done two months after initial treatment which showedgood response in the treatment area in all cases. After 5-34 months a pathological findingwas seen, which was treatment related in 3 cases and recurrent adenocarcinoma in onecase. In two cases, a new nodule appeared adjacent to the treatment area. It wasmisinterpreted as malignancy (5 months post-SBRT) in one case and treatment relatedchanges (11 months post-SBRT) in the other case. In one case, a new hypo-dense intramuscularopacity (17 months post-SBRT) was misinterpreted as tumor invasion to thechest wall. In the last case, a sudden episode <strong>of</strong> shortness <strong>of</strong> breath was co-incidental withevidence <strong>of</strong> worsening <strong>of</strong> the right hilar/peri-hilar thickening and new partial RULcollapse (34 months post-SBRT) which was misinterpreted as tumor recurrence. Furtherinvestigation in all cases resulted in change in primary diagnosis.Conclusion: Pathological findings after SBRT treatment for lung cancer are various innatures. They could be benign or malignant and they can mimic each other in theirradiological appearance which can cause misdiagnoses <strong>of</strong> these lesions. Radiologistshould be aware <strong>of</strong> these imaging pitfalls and try to avoid misinterpretation <strong>of</strong> CT imagesafter SBRT treatment for lung cancer.15 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Due to a special request, this presentation, which moreproperly belongs in the Vascular and Interventional<strong>Imaging</strong> section, appears here.Incidental lumbar spine pathology detectedon pre-uterine artery embolization MRIsD Boparai, L Wu, R Rebello<strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> and <strong>Department</strong> <strong>of</strong> Medicine, St. Michael’s Hospital,University <strong>of</strong> Toronto, CanadaBackground/Aims: This study is a retrospective cohort study comparing the number <strong>of</strong>incidental findings <strong>of</strong> lumbar spine pathology in women undergoing pelvic MRIs forpre-uterine artery embolization evaluation to women <strong>of</strong> a similar age undergoing pelvicMRIs for all other indications at St. Michael’s Hospital.Methods: The study consisted <strong>of</strong> looking at every patient undergoing a pre-UFE pelvicMRI over a two year period <strong>of</strong> time St. Michael’s Hospital who consented to the MRIDatabase. The comparison group consisted <strong>of</strong> women undergoing pelvic MR, during thesame time period, with the same protocol but for other indications. A similar number <strong>of</strong>exams were compared and the groups were age matched.The study utilized two blinded staff radiologists who analyzed sagittal images <strong>of</strong> theselected pelvic MRIs without knowing the indication <strong>of</strong> the study. In addition, theradiologist was only provided images <strong>of</strong> the lumbar spine; the remainder <strong>of</strong> the organswere covered so that the uterus or fibroids would not bias results. The radiologist wassimply asked to discern whether or not there is lumbar spine pathology and to specify theseverity, graded from 1 to 3. The size and volume <strong>of</strong> the uterus, a routine measurementon pre-UFE pelvic MRIs, will also be measured separately as ancillary data.Results: Using a chi-squared analysis to compare percentages <strong>of</strong> presence <strong>of</strong> lumbarspine pathology between MRI and UFE data sets, 79% <strong>of</strong> cases in MRI data set had ‘yes’for incidental lumbar spine pathology and 76% in the pre- UFE data set. Differencebetween 79% and 76% was not statistically significant with p=0.6515. Using analysis <strong>of</strong>covariance to compare the means <strong>of</strong> size between two data sets and adjusting for severityalso showed no significant differences.Conclusions: No significant difference in lumbar spine pathology seen on MRI betweenwomen undergoing pre-uterine artery embolization MRIs compared to those undergoingpelvic MRIs for all other indications.16 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Breast, MSK and Physics17 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Merits <strong>of</strong> five clinical dosimeters in an interventional radiology settingLeah Shuparski, Bairbre ConnollyPurpose: As the relative advantages and disadvantages <strong>of</strong> one dosimeter over anotherare unclear to the clinical interventionalist, our purpose was to evaluate the merits <strong>of</strong> avariety <strong>of</strong> dosimeters in a clinical interventional radiology (IR) suite.Method and Materials: Five dosimeters were evaluated: Dose-Area Product (DAP),Patient Exposure Management Network (PEMNET), MOSFETs, TLDs, and Gafchromicfilm. Each dosimeter was tested for linearity, reliability, accuracy and lower limit <strong>of</strong>detection (LLD) using a biplane fluoroscopy system. The merits <strong>of</strong> each dosimeter werethen assessed by simulating 5 common procedures on a tissue-equivalent,anthropomorphic phantom. The procedures simulated were G/GJ tube insertion, renalangiography, neuroangiography, CVL and chest tube insertions. Field size, table andimage intensifier height and beam orientation, among others, were used to standardize themock exam.Results: The LLD for MOSFETs and TLDs were 0.5 and 1.6 mGy respectively. TheLLD for film was 40 mGy. DAP meter measured doses greater than 10 mGy*cm 2 .PEMNET does not have a LLD, as it calculates exposure using machine parameters suc<strong>has</strong> kVp, mA and table geometry. Above their respective LLDs, all dosimeters exhibited alinear response with increasing fluoroscopy time (R 2 > 0.9) and agreed within 20% <strong>of</strong> thetrue dose measured using an ion chamber. PEMNET, DAP and MOSFETs provided adirect readout <strong>of</strong> entrance skin dose at the end <strong>of</strong> each examination, and performedreliably across a wide range <strong>of</strong> doses. TLDs performed well at low to high doses, but, likefilm, required at least 24 hours after exposure to derive a dose result. However, the TLDprocessing time was due to institutional factors, rather than an inherent TLDcharacteristic.Conclusion: For routine use, online dose measurement systems such as PEMNET orDAP are reliable and easy to use. When requiring a detailed knowledge <strong>of</strong> the entranceexposure, other dosimeters must be utilized. For low-dose applications, MOSFETs areideal due to their ability to provide skin exposure at specific locations, and can be readimmediately. Despite a higher LLD, film was preferred by some interventionalists, wh<strong>of</strong>ound it useful to see the dose distribution in addition to the peak dose.18 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>MRI-guided vacuum-assisted breast biopsy: Initial experiencePavel CrystalPurpose: To evaluate the accuracy <strong>of</strong> MRI-guided vacuum assisted breast biopsy(MRgVABB).Materials and Methods: We retrospectively reviewed the results <strong>of</strong> 135 consecutiveMRIg VABB between February 2006 and October 2008. Concordant benign biopsyresults were verified by excisional biopsy or by at least 6-months follow-up breast MRI.Results: Of 135 biopsies, core histology revealed 16 malignant (16/135, 12%), 29 highrisk(29/135, 21%), and 90 benign (90/135, 67%) lesions.Of 6 cases DCIS at MRgVABB, 2 were upgraded to invasive carcinoma (underestimationrate 33%) at lumpectomy. Of 29 high-risk lesions at MRgVABB, 11 were upgraded tomalignancy, all <strong>of</strong> which were DCIS (underestimation rate 38%) at surgery.Of 90 benign lesions at MRgVABB, repeat biopsy was suggested in 8 cases based onradiology-pathology discordance. Cancer was diagnosed at repeat biopsy in 4 cases.MRI stability without evidence <strong>of</strong> lesion progression or MRI lesion disappearance weredocumented in 71 cases while 11 patients were lost to follow-up.Overall accuracy <strong>of</strong> MRgVABB is 96.2%, while false-negative rate is 12.9%.All 8 discordant cases, including 4 false-negative cases, occurred among the first 60 casesor among the first 20 cases done by any one radiologist.Conclusion: MRgVABB is an accurate method for evaluating MRI detected otherwiseoccult lesions. Vigilant radiology-pathology correlation is required in order to avoiddelay in diagnosis <strong>of</strong> carcinoma. All high-risk lesions need excision in view <strong>of</strong> highunderestimation rate. There appears to be a learning curve in the performance <strong>of</strong>MRgVABB procedures.19 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Can DWI be a non invasive method to predict axillary metastasesin patients with biopsy proven breast carcinoma?Riham Eiada, Anabel M Scaranelo, Supriya R Kulkarni, Pavel CrystalJoint <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong>,University Health Network and Mount Sinai HospitalUniversity <strong>of</strong> TorontoPurpose: To determine the accuracy <strong>of</strong> diffusion-weighted-MR imaging (DWI) indetecting metastatic axillary lymph nodes in patients with new diagnosis <strong>of</strong> breast cancerundergoing staging breast MRI.Materials and Methods: From June 2008 to March <strong>2009</strong>, 109 axillary lymph nodeswere assessed in 74 patients with biopsy proven breast cancer (BI-RADS category 6)who underwent preoperative staging breast MRI. During the staging MRI, DWI wasacquired with b values <strong>of</strong> 50, 300, 700 and 1000 s/mm2 using a single shot echo-planarsequence and apparent diffusion coefficient (ADC) map was obtained automatically inreconstructed images. Visual assessment <strong>of</strong> DWI and ADC maps was performed by 2reviewers and classified using a five point chart. DWI signal intensity and ADC valueswere measured for ipsilateral axillary lymph nodes and a ratio <strong>of</strong> ADC/DWI usingdifferent b-values was recorded and compared for benign and malignant lymph nodesfrom final surgical pathology.Positive predictive value (PPV) was compared for visual assessment and for DWI (basedon ADC threshold).Results: Pathology results <strong>of</strong> sentinel node biopsy or axillary lymph node dissectionwere available for 62 DWI cases. The visual assessment showed sensitivity=84 %,specificity= 65%, PPV=86% and NPV= 61%. Our accuracy was 79% (p=0.000333).ADC (mean+/- SD x10-3 mm2/s) values obtained through calculation <strong>of</strong> different bvalues, were 0.80 and 0.66 respectively for malignant and benign lymph nodes (0.69,0.55, 0.42, 0.36 and 0.36, 0.27, 0.21, 0.17). Our threshold was 0.70 +/- 0.46, todifferentiate between benign and malignant nodes, and showed sensitivity=55 %,specificity= 58%, PPV=78% and NPV= 33%. Our accuracy was 56% (p=0.023).Multiple b values did not show significant precision over single b value.Conclusion: The metastatic axillary lymph node did not exhibit significantly alteredADC values compared to normal lymph nodes, however the visual assessment using afive point chart proved to be a significant tool. Adding DWI to standard dynamiccontrast-enhanced MRI may increase PPV in metastatic axillary lymph nodes in staging<strong>of</strong> BIRADS 6 breast cancer.20 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Potential contribution <strong>of</strong> computer-aided detection (CAD)to the sensitivity <strong>of</strong> full-field digital mammographyArifa Sadaf, Pavel CrystalAim: To assess potential contribution <strong>of</strong> computer-aided detection applied to full-fielddigital mammography (FFDM).Materials and Methods: Database search revealed 62 patients who have had FFDM atthe time <strong>of</strong> diagnosis and at least one standard FFDM 4-36 months before the diagnosis.Prior mammograms were reviewed retrospectively in non-blinded fashion in order toassess visibility <strong>of</strong> cancers. Mammographic characteristics <strong>of</strong> the malignant lesions wererecorded. CAD system (iCAD) was applied to all current and prior mammograms.Results: 58 out 62 cancers were visible on current mammogram, 4 cancers weremammographically occult (all 4 presented as palpable lesions) and were excluded.Mammographic features <strong>of</strong> 58 cancers included 25 masses, 22 calcifications, 5 masseswith calcification, and 6 areas <strong>of</strong> architectural distortion.CAD correctly marked 50 <strong>of</strong> 58 lesions on current mammogram. 8 lesions not marked byCAD included 3 masses, 2 masses with calcifications and 3 distortions. Sensitivity <strong>of</strong>CAD for detection <strong>of</strong> cancer on current mammogram was 86%.On prior mammogram 41 % (24 <strong>of</strong> 58) <strong>of</strong> cancers were visible on non blindedretrospective review. 46 % <strong>of</strong> these retrospectively visible cancers (11 out <strong>of</strong> 24) weremarked by CAD; these included 8 masses and 3 calcifications.Conclusion: CAD <strong>has</strong> marked 46% <strong>of</strong> retrospectively visible cancers at previousscreening round. CAD standalone sensitivity at the time <strong>of</strong> diagnosis was only 86%.Interpretation <strong>of</strong> FFDM using CAD <strong>has</strong> potential to improve mammographic sensitivity.21 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>MR imaging as a screening tool for early detection <strong>of</strong> intraarticular bleedin hemophilic children: A systematic reviewAndrea S. Doria, MD, MSc, PhD, Hospital for Sick Children, University <strong>of</strong> Toronto;Victor Blanchette, MDBackground: Early treatment <strong>of</strong> hemophilia (prophylaxis) <strong>has</strong> <strong>been</strong> shown to reduce thelong-term joint morbidity related to the development <strong>of</strong> arthropathy. <strong>Imaging</strong>examinations are appealing choices for diagnosis and follow-up <strong>of</strong> hemophilic jointchanges over time. MRI holds potential as a screening imaging modality for patientselection for secondary prophylaxis, targeting joints that can be treated and saved fromprogressive arthropathy.Objectives: To determine the level <strong>of</strong> evidence <strong>of</strong> results <strong>of</strong> studies related to screening<strong>of</strong> early intra-articular s<strong>of</strong>t tissue bleed with MRI in hemophilic children suitable toreceive prophylaxis, and with regard to improvement <strong>of</strong> functional status <strong>of</strong> joints overtime as measured by the World Federation <strong>of</strong> Hemophilia [WFH] Orthopedic joint scaleand Pettersson radiographic scale.Methods: An electronic literature search (January 1966 to March <strong>2009</strong>) was conductedto identify studies pertaining to the aforementioned objectives. The reviewersindependently analysed the studies to score the quality <strong>of</strong> evidence tables using modifiedcriteria for grading the internal validity <strong>of</strong> individual studies and the QUADAS (qualityassessment <strong>of</strong> studies <strong>of</strong> diagnostic accuracy included in systematic reviews) criteria.Results: The electronic literature search retrieved 85 (MEDLINE) and 84 (EMBASE)citations restricted to hemophilia. A total <strong>of</strong> 12 (752 participants) studies were chosen forthe review. The following bodies <strong>of</strong> evidence were evaluated:Overarching question: Effect <strong>of</strong> MRI screening <strong>of</strong> s<strong>of</strong>t tissue changes in hemophilicjoints on final (functional status <strong>of</strong> the joint measured by the WFH Orthopedic Score orby the Pettersson radiographic score) outcome measure: MEDLINE AND EMBASE,N=0.Key question #1: Diagnostic performance <strong>of</strong> MRI as a diagnostic tool for assessment<strong>of</strong> s<strong>of</strong>t tissue changes (hemarthrosis or synovial hypertrophy) in a hemophilic joint ascompared with clinical or laboratory data (construct validity), or biopsy data (criterionvalidity): MEDLINE, N=6; EMBASE, N=13 (combined key questions #1 and #4).Key question #2: Effect <strong>of</strong> intervention (prophylaxis) on intermediate (MRI evidence<strong>of</strong> cartilage degeneration) outcome measure: MEDLINE, N=11, EMBASE, N=6.Key question #3: Effect <strong>of</strong> intervention (prophylaxis) on final (functional status <strong>of</strong> thejoint) outcome measure: MEDLINE, N=68, EMBASE, N=65.Seven out <strong>of</strong> 8 studies included in the analysis (1 fair quality, and 6 poor qualityevidence) suggested a beneficial effect <strong>of</strong> prophylaxis on future orthopedic and/or25 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Automatic contrast enhancement <strong>of</strong> cerebral white matter lesions in FLAIR MRIApril Khademi 1,3 , Anastasios Venetsanopoulos 1,2 , Alan Moody 3,41 <strong>Department</strong> <strong>of</strong> Electrical and Computer Engineering, University <strong>of</strong> Toronto,2 <strong>Department</strong> <strong>of</strong> Electrical and Computer Engineering, Ryerson University,3 <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Department</strong>, Sunnybrook Health Sciences Center,4 <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong>, University <strong>of</strong> Toronto.Introduction: As white matter lesions (WML) are an independent risk factor orintermediate surrogate <strong>of</strong> stroke [1][2], image processing algorithms are being heavilyresearched to automatically quantify such neurological diseases. Image processors are aset <strong>of</strong> s<strong>of</strong>tware algorithms which automatically operate on the images based onmathematical principles and theories. Such techniques are valuable in medical imagingas they can produce robust, reliable and repeatable results for segmentations orclassifications. As FLAIR MRI is the preferred imaging modality for WML detection, itis important to tune the algorithms specifically to FLAIR. Although FLAIR MRIs <strong>of</strong>ferexcellent discrimination between anatomy and pathology, artifacts, such as partialvolume averaging (PVA) and thermal noise corrupt the image and pose challenges toautomated techniques. To combat these image degradations, it is possible to first employan automatic contrast enhancement scheme for better separation (in terms <strong>of</strong> intensity)between pathology and background. Highlighting pathology and suppressing normalappearing cerebral regions allows image processing schemes, such as segmentationand/or classification, to achieve higher accuracy. Consequently, this work concerns thedevelopment <strong>of</strong> a novel contrast enhancement algorithm for FLAIR-weighted cerebralMRI with white matter lesions (WML). As such a technique separates WML and brainwith excellent results, a thresholding-based WML segmentation algorithm is alsopresented.Methods: To isolate the cerebral structures, a novel brain extraction algorithm techniqueis first employed on the FLAIR MRI. Based on the brain extracted result, the proposedmethod utilizes both a robust estimate <strong>of</strong> edge magnitude and intensity values todiscriminate between pathological and non-pathological information. These two featuresare combined through several transformations, such that WML are highlighted, andnormal appearing white/gray matter are suppressed. The technique utilizes informationsolely computed from each image and thus adapts to the input image’s characteristics.For a more detailed outline <strong>of</strong> the algorithm, please see [3]. For the segmentation aspect,a threshold is automatically set to the value T = μ + σ, where the mean μ and variance σare estimated from the contrast enhanced image’s histogram. All pixels which are greaterthan this threshold are labeled WML.Materials: A retrospective study was performed on images acquired from symptomaticpatients who were referred for cerebral FLAIR imaging. The FLAIR sequence used <strong>has</strong>the following parameters: TR 9000 ms, TE 110 ms, TI 2500 ms, FOV 180x240 mm,matrix 176x256, 4 mm slice thickness, 2 mm gap and two averages. To test the27 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>enhancement scheme, 5 patients with WML were used, resulting in 18 images (slices) intotal which contain WML.Results: To test the enhancement scheme, the 18 images (slices) were used and theresults for several images are shown in Figure 1. To quantify the performance <strong>of</strong>contrastenhancement schemes either objectively or subjectively is difficult [4]. Someauthors have proposed local contrast measures to compute the Contrast ImprovementRatio (CIR) [4], which compares the contrast <strong>of</strong> an image before and after contrastenhancement. To measure the local enhancement <strong>of</strong> the lesions, several small regionsfrom each image were chosen to compute the CIR (typically, regions were approximately25x25 pixels in size). Each region contained normal brain tissue and WML. These valuesare shown in Table 1, and the average value over 18 images is 40%.Conclusions: This work presents a novel contrast enhancement scheme for WML incerebral FLAIR. The results are promising, as the average Contrast Improvement isroughly 40%. Additionally, not only are the results visually appealing, but a simpleautomatic computed threshold is able to segment the lesions. The next stages <strong>of</strong> thisresearch include WML segmentation validation.References:[1] N. Altaf, L. Daniels, P.S. Morgan, J. Lowe, J. Gladman, S.T. MacSweeney, A.Moody, and D.P. Auer, “Cerebral white matter hyperintense lesions are associatedwith unstable carotid plaques,” EU J. Vascular/Endovascular Surg., 31, pp. 8–13,2006.[2] N. Altaf, A. Beech, S. Goode, J. Gladman, A. Moody, D. Auer, and S. MacSweeney,“Carotid intraplaque hemorrhage detected by magnetic resonance imaging predictsembolization during carotid endarterectomy,” J. Vascular Surgery, 46(1), pp. 31–36,2007.[3] A. Khademi, A. Venetsanopoulos, A. Moody, “Incorporation <strong>of</strong> Intensity and EdgeInformation for Contrast Enhancement <strong>of</strong> FLAIR MRI with White Matter Lesions”,IEEE ISBI <strong>2009</strong> (accepted).[4] C.Wyatt, Y.-P.Wang, M. T. Freedman, M. Loew, and Y.Wang, BiomedicalInformation Technology, Chapter 7., pp. 165–169, Elsevier, ‘07.28 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Figure 1:Top: brain extracted original images;Middle: contrast enhanced images;Bottom: binary segmentation resultsTable 1: CIR results for 18 images29 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>A post-processing method for generatingarbitrary T2-weighted contrast in MRIMarshall S. Sussman, Gustav Andreisek, Ali Naraghi, John S. Theodoropoulos,Claire Zhao, Norman Young, Tallal C. Mamisch, Lawrence M. WhitePurpose: To evaluate the feasibility and accuracy <strong>of</strong> a synthetic-TE magnetic resonance(MR) post-processing technique in the context <strong>of</strong> meniscal and cartilage abnormalities <strong>of</strong>the knee.Material and Methods: The knees <strong>of</strong> twenty-four patients were evaluated with standardT2-weighted fast spin-echo (FSE) sequences. In addition, multi-echo fast-gradient-echo(FSGRE) sequences were performed for the generation <strong>of</strong> synthetic-TE images withvariable T2 (or T2*)-weighted contrast using a new synthetic-TE analysis tool that wasincorporated directly into the picture archiving and communication system (PACS).Sensitivities, specificities and accuracies for detection <strong>of</strong> meniscal and cartilage lesionswere calculated using surgery as reference standard.Results: The standard T2-weighted MR sequences had overall sensitivities, specificities,and accuracies <strong>of</strong> 100%, 88%, and 95% for the diagnosis <strong>of</strong> meniscal tears.Corresponding sensitivities, specificities, and accuracies <strong>of</strong> synthetic-TE MR imagegeneration were 92%, 88%, and 90%.Conclusions: The synthetic-TE technique was shown to be a technically viablealternative for the evaluation <strong>of</strong> menisci to standard T2-weighted images. The results <strong>of</strong>this study demonstrated that the synthetic-TE approach allowed for the assessment <strong>of</strong>meniscal abnormalities with high sensitivity and specificity.30 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Neuroimaging31 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Comparison <strong>of</strong> Gad<strong>of</strong>osveset trisodium (Vasovist) steady state enhanced magneticresonance angiography (MRA) with first pass and three dimensional time <strong>of</strong> flightMRA at 1.5 Tesla in the follow-up <strong>of</strong> coiled cerebral aneurysmsDaniel Baxter, Walter Montanera, Dipanka Sarma,Sean Symons, Richard Farb, Thomas MarottaPurpose: To compare three different MRA techniques in the follow-up <strong>of</strong> coiledcerebral aneurysms using Gad<strong>of</strong>osveset trisodium (Vasovist) steady state enhancedMRA, first pass, and 3D TOF MRA techniques at 1.5 T.Background: Gad<strong>of</strong>osveset trisodium (Vasovist) is an injectable contrast solution usedin magnetic resonance imaging that binds reversibly to albumin. This albumin bindingcharacteristic extends the vascular life time <strong>of</strong> the agent and allows for longer vascularimaging time with steady state imaging. This longer vascular imaging time allowscollection <strong>of</strong> more raw imaging data, increased matrix size, and higher spatial resolutionMR images. Higher spatial resolution MR angiography (MRA) should be useful indetecting residual flow in coiled cerebral aneurysms.Materials and Methods: This is a pilot study. Ten sequential patients followed forcoiled cerebral aneurysms at St. Michael’s Hospital underwent Gad<strong>of</strong>osveset trisodium(Vasovist) steady state enhanced MRA, first pass, and 3D TOF MRA techniques at 1.5 T.Three blinded independent expert interventional neuroradiologists prospectivelyevaluated the MRA techniques based on three dichotomous questions. 1) Is theresatisfactory vessel conspicuity? 2) What size is the coiled aneurysm remnant? 3) Doyou recommend retreatment or follow up? The first pass contrast enhanced MRA servedas the “gold standard.” A consensus response for the three independent interventionalneuroradiologist readers was derived on the basis <strong>of</strong> majority opinion.Results: To date fourteen coiled aneurysms were evaluated using 3D time <strong>of</strong> flightMRA, first pass, and steady state Gad<strong>of</strong>osveset trosodium enhanced MRA. Satisfactoryconspicuity <strong>of</strong> the peri-aneurysmal vascular anatomy was present in 12 (86%) TOFMRAs, 14 (100%) first pass MRAs, and 14 (100%) steady state MRAs. Five residualaneurysm remnants greater than 2 mm were described on the first pass MRAs. Of these,four were identified on TOF MRA (sensitivity 80%, specificity 89%), and five weredemonstrated on steady state MRA (sensitivity 100%, specificity 78%). The oneaneurysm remnant not seen on TOF MRA measured 5 mm.Conclusion: Gad<strong>of</strong>osveset trisodium steady state MRA is a reliable technique for thesurveillance <strong>of</strong> coiled cerebral aneurysms and is superior to the TOF MRA for thispurpose.32 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Sex differences in the human corpus callosum microstructure:T2 myelin-water imaging versus diffusion tensor imagingF. Liu 1 , L. Vidarsson 2 , and A. Kassner 1,31 Physiology and Experimental Medicine, Hospital for Sick Children, Toronto, Canada,2 Diagnostic <strong>Imaging</strong>, Hospital for Sick Children, Toronto, Canada,3 Dept. <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong>, University <strong>of</strong> Toronto, Toronto, Canada.Introduction: The corpus callosum (CC) plays an important role in relaying sensory,motor and cognitive function between the cerebral hemispheres. Females seem to employa greater degree <strong>of</strong> bilateral hemispheric activity than males (1) and also have a largercallosal area in proportion to brain volume (2) which suggests that a larger number <strong>of</strong>fibres are passing through. We have previously shown that fiber density is higher infemales compared to males in subdivisions <strong>of</strong> the CC using diffusion tensor imaging(DTI) (3). We hypothesize that these sex differences are due to a difference in myelincontent. Short-T2 myelin-water imaging <strong>has</strong> previously <strong>been</strong> used to shed light on brainmicrostructure (4-5). In this study we have compared short T2 myelin-water imaging toDTI in the corpus callosum <strong>of</strong> healthy volunteers.Materials and Methods: Twenty healthy age matched volunteers (10 male, 10 females,age 19-31 years) underwent MR imaging. All subjects were right-handed with no knownneurological disease. A 5 echo myelin-water imaging protocol was adapted to this studyas described previously (4). <strong>Imaging</strong> parameters used for the 5 echo multi-slice spin echoimages were as follows: TE/TR = 8,23,33,74,110 / 698,713,723,764,800, NSA = 2, FOV= 24 cm, matrix = 128x128, bandwidth = 15.6 kHz and 6 slices (4mm thickness with a1 mm gap). In addition to the T2 myelin-water images, DTI was performed using 15 noncollineardirections <strong>of</strong> diffusion sensitization with an echo planar readout (b-value=0 and1000s/mm 2 , matrix =128x128, FOV <strong>of</strong> 240mm; slice thickness 2mm, number <strong>of</strong> slices54, TE=74ms, 4NEX). Total scan time was 30 mins for both myelin-water images andDTI. DTI datasets were spatially registered using AIR (vs 3.0) and post-processed usingDTI Studio (vs 2.4). Regions <strong>of</strong> interest (ROIs 18 pixels and 8 pixels, respectively) wereplaced in six subdivisions <strong>of</strong> the corpus callosum according to the Witelson scheme(6): CC2-Genu, CC3-Rostral body, CC4-Anterior midbody, CC5- Posterior midbody,CC6-Isthmus, CC7-Splenium. For each ROI, the average myelin-water content (4), theaverage fractional anisotropy (FA), and the fiber density index (FDi) (7) were computed.An unpaired Student’s t-test was used to compare all variables between male and femalevolunteers.Results: When compared males to females, a significant myelin-water fraction decreasewas found in CC3 (p
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Discussion: These findings suggest that in areas where fibers are less densely packed, there ismore myelin content. Significant differences were observed in corpus callosum-rostral body, andsplenium by using myelin-water fraction, which indicates a link between myelin content andgender differences.References:1. Crow et al. Neuropsychologica 1998.2. Mitchell et al. AJNR 2003.3. Kassner et al. ISMRM 2007 #1578.4. Vidarsson et al. MRM 2005.5. Laule et al. Neurotherapeutics 2007.6. Witelson, Brain 1989.7. Roberts et al. AJNR 2005.p
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Exhausted cerebral autoregulation is spatially associated with cortical atrophyJ. Fierstra, J. Poublanc, H. Wang, J. Han, A. Crawley, J. Fisher, D.J. MikulisThe Toronto Western Hospital, Toronto, ONObjectives: The physiological impact <strong>of</strong> severely impaired cerebral autoregulatoryvascular reactivity on gray matter integrity is unknown. We hypothesized that corticalgray matter supplied by a defective vascular system with exhausted dilatoryautoregulation reserve will show evidence <strong>of</strong> cortical atrophy.Methods: 250 BOLD-MRI cerebrovascular reactivity (CVR) studies were reviewed toidentify subjects with severe unilateral impairment in CVR (impaired blood flowresponse to a vasoactive stimulus such as a change in PetCO2.), vasodilatory reserve(negative CVR) but with normal appearing gray matter on FLAIR. Patients with lacunarinfarcts in the white matter were excluded. 17 patients were identified each having a highgrade stenosis or occlusion <strong>of</strong> the ICA or MCA on one side regardless <strong>of</strong> etiology,secondary to Moyamoya, atherosclerosis, or unknown. CVR studies were performed byapplying precision control <strong>of</strong> imposing acute transient vasodilatory stimulus end-tidalpCO2 CO2 between baseline (40mmHg) and to 50mmHg, (Respiract, TRI, Toronto,Canada) during BOLD MRI acquisition on a GE T HDX MRI system. 1 A D T1-weightedvolume (voxel 0.78 x 0.78 x 2.2 mm) was acquired and analyzed for cortical thicknessusing freesurfer (http://surfer.nmr.mgh.harvard.edu/). CVR and cortical thickness mapswere overlapped to determine a ROI encompassing the region <strong>of</strong> negative impaired CVR.This ROI was mirrored to the normal hemisphere providing a normal versus abnormalhemisphere ROI comparison in each subject. Mean cortical thickness between right andleft hemisphere ROIs for each subject was measured and a paired t-test was applied.Results: The ROI with negative impaired CVR showed thinner cortex(2.23 mm +/- 0.077) than the corresponding contra lateral side (2.42 mm +/- 0.052)(p = 0.0005) in 16 <strong>of</strong> the 17 cases. Mean cortical thickness was 2.23 mm +/- 0.077 on theabnormal side, and 2.42 mm +/- 0.052 on the normal side (p = 0.0005). Figure 1 showsthe relationship between the spatial extent <strong>of</strong> abnormal impaired CVR (blue) and thespatial extent <strong>of</strong> cortical thinning (light blue) in one subject, (decreased extent <strong>of</strong> lightblue in right hemisphere = thinner cortex and increased extent <strong>of</strong> blue in right hemisphere= negative CVR).Conclusions: The data indicates that a spatial correspondence exists between exhaustion<strong>of</strong> autoregulatory capacity, vasodilatory capacity and cortical thinning. The findingsimply that relate the inability to augment flow in response to metabolic stimuli, (as is alsonormally seen with neuronal activation), may be deleterious to the health <strong>of</strong> thepreservation <strong>of</strong> gray matter.References:1. Vesely et al. MRM 2001;45:1011-1013.35 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Figure 1:36 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Comparative detectability <strong>of</strong> magnetic susceptibility signals seen on EPI-GRE,MPGR and VEN BOLD sequences using 3T MRI: Preliminary resultsVitaly Sygal, Allan J Fox, Peter Howard, Sean P Symons,Richard I Aviv, Robert YeungBackground and Significance: Detecting magnetic susceptibility plays an importantrole in brain imaging, particularly in identifying blood products (deoxyhemoglogbin andhemosiderin) in the setting <strong>of</strong> disorders like cerebral amyloid angiopathy, hypertensivevasculopathy and traumatic brain injury. Echo-Planar <strong>Imaging</strong> Gradient Echo (EPI-GRE)and Multi-Planar Gradient Echo (MPGR) have traditionally <strong>been</strong> the sequences used atour institution for this purpose. A new sequence called Venous Blood OxygenationLevel Dependent MRI (VEN_BOLD) is believed to be more sensitive at detectingmagnetic susceptibility.Materials and Methods: This is a retrospective study that included patients thatunderwent 3T MRI <strong>of</strong> the head with all three sequences <strong>of</strong> interest between July toSeptember 2008. Patients with extensive artifact, intraparenchymal hematomas, laminarnecrosis, subarachnoid blood and tumors were excluded. A board-certifiedneuroradiologist analyzed each <strong>of</strong> the three sequences for each patient in a blindedfashion and identified all areas <strong>of</strong> magnetic susceptibility. Results were comparedbetween the three sequences.Results: There were a total 80 patients in this study with 103 lesions with magneticsusceptibility detected by at least one sequence. There were 78 true lesions and 25 thatturned out to be either a vessel or developmental venous anomaly on BOLD. EPI-GREdetected 21 (27%), MPGR detected 37 (47%) and BOLD detected 75 (96%) <strong>of</strong> the truelesions. Of the 25 false lesions detected, 21 were <strong>made</strong> by EPI and 12 by MPGR.BOLD detected 39 (50%) lesions that were not picked up by either EPI-GRE or MPGR.In contrast, 2 lesions (3%) were detected only by MPGR and none were detected only byEPI-GRE. Nineteen lesions (24%) were detected by all three sequences. Regardingpatients, BOLD detected at least one lesion in 7 patients while EPI-GRE and MPGR didnot detect any lesions in these patients.Conclusion: BOLD was superior to both EPI-GRE and MPGR in detecting lesions andpatients with intracranial magnetic susceptibility. BOLD was also useful indifferentiating true lesions from vessels and developmental venous anomalies. Theresults support the use <strong>of</strong> VEN-BOLD as the sequence <strong>of</strong> choice in detecting intracranialmagnetic susceptibility.37 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Assessment <strong>of</strong> cerebrovascular reactivity using real time BOLD MRIin children with Moyamoya disease: A feasibility studyBejoy Thomas; MD; DNB*, William Logan; MD; FRCPC**, Logi Vidarsson; PhD*,Elizabeth Donner; MD; FRCPC**, Manohar Shr<strong>of</strong>f; MD; FRCPC*<strong>Department</strong>s <strong>of</strong> Diagnostic <strong>Imaging</strong>* and Neurology**, The Hospital for Sick Children,University <strong>of</strong> Toronto, Toronto, Ontario, CanadaIntroduction: Assessment <strong>of</strong> cerebrovascular reactivity (CVR) is critical in decidingrevascularization procedures in cerebrovascular steno- occlusive diseases like moyamoyadisease. In a clinical context CVR can be estimated using MRI by altering PaCO2through changes in ventilation and measuring the resultant BOLD signal changes. Realtime BOLD MRI (rtfMRI) can analyze functional imaging studies at the time <strong>of</strong> /immediately after scanning the patient. This is a feasibility study to test the reliability andvalidity <strong>of</strong> assessment <strong>of</strong> CVR with rtfMRI (rtCVR) in comparison to standard <strong>of</strong>f- lineprocessing in children with moyamoya disease who are potential candidates for surgicalcerebral revascularization.Methods: Seven patients (ages 4 – 17 years, 4 female, nine sessions <strong>of</strong> study) withmoyamoya cerebral arteriopathy had undergone <strong>of</strong> BOLD MRI CVR studies either on a1.5T or on a 3T scanner (Achieva, Philips, Best, Netherlands) for clinical evaluation <strong>of</strong>potential surgical cerebral revascularization. The PaCO2 was manipulated by deliberatebreath holding for 30 seconds followed by 60 seconds <strong>of</strong> free breathing while the BOLDMRI acquisition in co-operative patients. Three patients who underwent the study undergeneral anaesthesia (GA), the box car times were 120 seconds each. One patient hadundergone CVR study initially without and later with GA. One patient had undergoneCVR study initially without and later with GA. A rise <strong>of</strong> end tidal PCO2 <strong>of</strong> 8 to 10 mmHg took between 60 to 100 seconds in the ventilated patients. All cases were analyzedwith standard <strong>of</strong>f-line analysis (Stimulate: Strupp, J. P. “Stimulate: A GUI Based fMRIAnalysis S<strong>of</strong>tware Package”, NeuroImage (1996), 3: S607) and also with the vendorsupplied rtfMRI s<strong>of</strong>tware. Blinded evaluation for interrater reliability <strong>of</strong> the quality <strong>of</strong>rtCVR on a ‘0’ to ‘3’ scale and for validity <strong>of</strong> real time results compared to <strong>of</strong>f-lineprocessing was performed.Results: There was a high interrater reliability noted among the two independent ratorsfor assessment <strong>of</strong> quality for clinical utility <strong>of</strong> real time results (k = 0.77). The rtCVR wascomparable to <strong>of</strong>f-line results with regard to adequacy <strong>of</strong> the activation, presence orabsence <strong>of</strong> abnormal reactivity, location, pattern and extent <strong>of</strong> abnormal activation(absence <strong>of</strong> response or paradoxical response) when present (sensitivity <strong>of</strong> 88.8%,specificity 100%). In one <strong>of</strong> the studies the data could not be processed with rtfMRI dueto technical issues were as <strong>of</strong>f- line analysis could still be possible. In another patientwith excessive movement had to have a repeat study under GA as the results wereinconclusive in both <strong>of</strong>f-line and rtfMRI analysis. Overall the quality and validity <strong>of</strong>activation was better in patients who underwent the study under GA with intubation.38 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Conclusion: rtCVR is feasible and the results are comparable to that <strong>of</strong> standard <strong>of</strong>f- lineanalysis in this series <strong>of</strong> cases. The results from <strong>of</strong>f-line analysis are available onlyseveral hours or days after the MRI <strong>has</strong> <strong>been</strong> completed. This delay precludes immediateassessment <strong>of</strong> the success <strong>of</strong> the CVR study or the need to repeat it while the patient isstill in the scanner. rtfMRI analysis can overcome this difficulty. However this method<strong>has</strong> to be standardized in each institution and for the vendor s<strong>of</strong>tware before routineclinical use.39 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Dynamic susceptibility contrast MRI in acute ischemic stroke:Surrogate measures <strong>of</strong> BBB permeability for theprediction <strong>of</strong> hemorrhagic transformationRebecca E. Thornhill 1,2 , Shuo Chen 1 , Wael Rammo 1 ,David J. Mikulis 3 , and Andrea Kassner 1,21 Dept. <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong>, University <strong>of</strong> Toronto;2 Dept. Physiology & Experimental Medicine, Hospital for Sick Children;3 Dept. <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong>, Toronto Western Hospital.Objectives: Therapeutic use <strong>of</strong> recombinant tissue plasminogen activators (rt-PA) inacute ischemic stroke (AIS) is currently limited to patients presenting ≤4.5h post-ictus,due to the increased risk <strong>of</strong> hemorrhagic transformation (HT) 1 . It <strong>has</strong> <strong>been</strong> shown thatpermeability MRI followed by tracer-kinetic modelling can be used to predict HT 2 .However, recent work suggests that information relating to blood-brain barrierpermeability can be more rapidly extracted from the recirculation-p<strong>has</strong>e <strong>of</strong> routine‘dynamic susceptibility contrast’ (DSC) MRI images 3-5 . Our purpose was to evaluate fourdistinct DSC parameters in discriminating between AIS patients who will proceed to HTand those who will not.Methods: Eighteen AIS patients were examined within 6 hours <strong>of</strong> symptom onset. Allimaging was performed on a 1.5 T clinical MRI system (GE Signa LX 12.0, Milwaukee,WI). DSC imaging consisted <strong>of</strong> a single-shot EPI scan with TR 1725 ms, TE 31.5 ms,FOV 240 mm, matrix 96×64, flip angle 90º, slice-thickness 5 mm, 17 slices, and anacquisition time <strong>of</strong> 86 s. Gadodiamide was injected as a bolus (Omniscan, GE, USA) atthe initiation <strong>of</strong> DSC. HT was determined by follow-up CT or MRI 24-72 h later. Datawere analyzed <strong>of</strong>fline. Two regions <strong>of</strong> interests (ROIs) were defined on diffusionweightedMRIs, one within the infarct and another within the homologous location in thecontralateral hemisphere and then copied to the equivalent DSC images. Mean rR, 3 PeakHeight, 4 %Recovery, 4 and Slope <strong>of</strong> the ΔR 2*v. time curve between 50 and 60 s postinjection5 were recorded (FIG.1) and data grouped based on follow-up HT-status. Foreach parameter, differences between ROIs as well as between HT and non-HT patientswere assessed using Wilcoxon matched pairs and Mann-Whitney U tests, respectively.Results: Eight patients proceeded to HT. While the mean rR for infarcts wassignificantly greater than for contralateral ROIs (0.18±0.02 v. 0.08±0.01, P
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>second perfusion scans, these two measures may provide convenient surrogates for DCE-MRI in the setting <strong>of</strong> acute ischemic stroke.References:1. Hacke W et al. NEJM 2008;359:1317-1329.2. Kassner A et al. AJNR 2005;26:2213-2217.3. Kassner A et al. JMRI 2000;11:103-113.4. Lupo JM et al. AJNR 2005;26:1446-1454.5. Bang OY et al. Ann Neurol 2007;62:170-176.FIG. 1: A ΔR 2 * v. time curve (ΔR 2*measured ), as well as its gamma-variate fit (ΔR 2*fit ). FourDSC parameters were calculated: rR (C/A), Peak Height (A), % Recovery = [100 x (A-B)/A], and Slope = slope <strong>of</strong> ΔR 2*measured (t) between 50 and 60 s post-injection.41 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Characterization <strong>of</strong> carotid plaque hemorrhage:A CT angiography and MR direct thrombus imaging studyJM U-King-Im, AJ Fox, RI Aviv, P Howard, R Yeung, AR Moody, S SymonsSunnybrook Health Sciences Centre, Toronto, CanadaPurpose: Decision-making regarding revascularization in carotid atherosclerosis isbased on luminal narrowing. There is, however, growing evidence that morphologicalfeatures <strong>of</strong> vulnerable plaques, such as intraplaque haemorrhage (IPH), ruptured fibrouscap or large lipid core, may be better predictors <strong>of</strong> stroke risk than luminal stenosis. MR-IPH is a recent but robust technique, able to detect IPH in vivo with excellent diagnosticaccuracy and reproducibility. The main objective <strong>of</strong> this study was to identify CTangiography (CTA) features which may predict presence <strong>of</strong> carotid IPH, as defined byMR-IPH.Methods: 167 consecutive patients (Mean age 69, SD 12.8, 58 females) underwent MR-IPH and CTA within 3 weeks. 153 patients were symptomatic, with suspected strokes orTIAs. MR-IPH was performed at 1.5 T, using neurovascular p<strong>has</strong>ed-array coil, as acoronal T1-weighted magnetization-prepared 3D GRE acquisition with fat -suppression(TR 10.3 ms, TE 4.0 ms, TI 20 ms, FOV 350 × 300 mm). MR-IPH was reviewed by one<strong>of</strong> four neuroradiologists, as to presence or absence <strong>of</strong> IPH. CTA was performed usingeither a 4 or 64 slice machine, using standard angiography protocols. Images werereviewed in the axial plane and on coronal and sagittal MPR images. CTA was evaluated,blinded to MR-IPH findings, for (1) plaque density (2) presence or absence <strong>of</strong> plaqueulceration. Plaque density was defined as mean HU <strong>of</strong> plaque at site <strong>of</strong> maximumstenosis and two sections above and below, measured using circular ROI in non-calcifiedportions. Plaque ulceration was defined as contrast outpouching into plaque at least 2 mmdeep on any single plane.Results: 15 arteries were excluded due to occlusions or previous surgery, yielding 319arteries for analysis. MR-IPH showed 56 cases <strong>of</strong> IPH. Mean CT plaque density washigher for plaques with MRI-defined IPH (HU 47) compared to without IPH (HU 43)(p = 0.02). However, significant overlap between distribution <strong>of</strong> plaque densities suggestthat plaque density is <strong>of</strong> limited value in distinguishing between the two groups.CT plaque ulceration had excellent diagnostic accuracy for presence <strong>of</strong> MRI-defined IPH(Sensitivity 80%, Specificity 93%, PPV 72% and NPV 95%).Conclusion: Presence <strong>of</strong> CT plaque ulceration, but not plaque density, was useful forprediction <strong>of</strong> MRI-defined IPH.Reference:1. Moody AR et al, Characterization <strong>of</strong> complicated carotid plaque with MR directthrombus imaging. Circulation 2003 Jun; 107:3047-52.42 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>DTI and cerebrovascular reactivity MR imagingin the developing swine brainJeff D. Winter 1 , Stephanie Dorner 2 , Joe Fisher 3,4 , Garry Detzler 1 , Andrea Kassner 1,51 Physiology and Experimental Medicine, Hospital For Sick Children;2 Thornhill <strong>Research</strong> Inc.;3 <strong>Department</strong> <strong>of</strong> Anesthesiology, University Health Network, University <strong>of</strong> Toronto;4 <strong>Department</strong> <strong>of</strong> Physiology, University <strong>of</strong> Toronto;5 <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong>, University <strong>of</strong> Toronto, Toronto, CanadaIntroduction: The pig brain <strong>of</strong>fers a useful neuroimaging model to investigate pediatricbrain injury and development because it is similar to humans in size, timing <strong>of</strong> braingrowth, cerebrovasculature and grey:white matter ratio (1). Previous neuroimagingstudies have characterized different aspects <strong>of</strong> human brain development, includingstructural changes in brain volume, cortical thickness and cortical folding (2). Toinvestigate developmental changes in tissue microstructure, such as myelination,researchers have employed diffusion tensor imaging (DTI), an MRI technique thatquantifies tissue water self-diffusion magnitude and directionality (3). One aspect <strong>of</strong>brain development that <strong>has</strong> not <strong>been</strong> fully characterized is vessel function. This can beassessed using cerebrovascular reactivity (CVR), a measure <strong>of</strong> the cerebral blood flow(CBF) response to a vasoactive stimulus (e.g., carbon dioxide). Using MR measures <strong>of</strong>CBF combined with controlled manipulation <strong>of</strong> the subject’s end-tidal partial pressure <strong>of</strong>CO 2 (PetCO 2 ) it is possible to generate high-quality and reproducible CVR images <strong>of</strong> theentire brain. Although widely used in adults, this method <strong>has</strong> yet to be applied in animalmodels. Our goal for this study is to demonstrate the feasibility <strong>of</strong> generating CVRimages using controlled PetCO 2 manipulation in a pig model <strong>of</strong> normal brain maturation,and to use this method to investigate changes in CVR in relation to DTI measures <strong>of</strong>microstructural changes.Methods: Seven Yorkshire pigs (1 - 3 months <strong>of</strong> age) were scanned on a 1.5 T GE SignaMRI scanner. Each animal was induced, intubated and mechanically ventilated.Anesthesia was maintained with an intravenous infusion <strong>of</strong> ketamine and midazolam. Weperformed DTI with 25 independent diffusion directions (b = 700 s/mm 2 ), echo time (TE)= 72 ms, repetition time (TR) = 5.5 s, field-<strong>of</strong>-view (FOV) = 160 mm, matrix size =128×128 and slices (4.5 mm thick) = 16. For CVR imaging, we acquired blood-oxygenlevel-dependent(BOLD) MRI data to provide an indirect measure <strong>of</strong> the changes in CBF.BOLD imaging was performed using standard single-shot echo-planar imaging (EPI) atthe same slice positions as the DTI acquisition. <strong>Imaging</strong> parameters included: TE = 40ms, TR = 2 s, FOV = 160 mm, matrix size = 64×64, slices (4.5 mm thick) = 16 andvolumes = 270. During BOLD imaging we applied a controlled cerebrovascular stimulusthat consisted <strong>of</strong> four square-wave cycles <strong>of</strong> hypercapnia (~ 55 mmHg for 60 s) andnormocapnia (~ 40 mmHg for 60 s). This was achieved using a computer-controlled gasdelivery system in combination with a sequential gas delivery circuit (RespirAct TM ,Thornhill <strong>Research</strong> Inc., Toronto, Canada), which continuously recorded PetCO 2 (4).43 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Diffusion tensor imaging post-processing was performed on the MRI scanner to generatemeasures <strong>of</strong> the apparent diffusion coefficient (ADC) and fractional anisotropy (FA). Allother post-processing was performed <strong>of</strong>fline using FSL and Matlab scripts. For theBOLD analysis, we matched the PetCO 2 and BOLD MRI time courses by estimating thetime delay between PetCO 2 and whole-brain BOLD signal changes. Once in p<strong>has</strong>e, wecalculated CVR (% ΔMR signal/mmHg CO 2 ) on a pixel-by-pixel basis from the slope <strong>of</strong>the regression <strong>of</strong> % MR signal with PetCO 2 . Next, we semi-automatically identifiedregions <strong>of</strong> cortical grey matter (CGM), cortical white matter (CWM), deep GM (DGM)and extracted mean values for CVR, ADC, and FA. We assessed the changes in ADC,FA and CVR during development using curve estimation <strong>of</strong> these parameters in relationto body weight.Results: Figure 1 provides a representative CVR map and the BOLD MRI time seriesfor all grey matter overlaid with the fitted PetCO 2 model. No trends were observed forADC data. Significant positive log-linear relationships between FA and body weightexisted in the CWM (r = 0.96) and the DGM (r = 0.97) (Figure 2a). In contrast, CVRdemonstrated a negative log-linear relationship with body weight in the DGM (r = 0.79)(Figure 2b).Discussion: In this study we found a significant log-linear FA change duringdevelopment in WM regions, which is similar to human brain maturation. The CVRresults suggest alterations in cerebrovascular function may occur at different stages <strong>of</strong>development. We also demonstrated the feasibility <strong>of</strong> CVR imaging with controlledPetCO 2 manipulation in an animal model. Together, these results suggest that the pig is apromising model for basic neurodevelopmental research and studies <strong>of</strong> pediatric braininjury and disorders. The ability to collect CVR images in pigs using controlled CO 2manipulation may enhance these future studies with regional information on vascularfunction.References:1. Dobbing J, et al., Early Hum Dev, 3:79-83 (1979).2. Durston S, et al., J Am Acad Child Adolesc Psychiatry, 40:1012:20 (2000).3. Mukherjee P et al., Radiology, 221:349-358 (2001).4. Prisman E et al., JMRI, 27:185-91 (2008).44 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Figure 1. Representative CVR map and the correspondingBOLD times-series with the fitted PetCO 2 model for a 2 monthold pig.a)0.4b)0.10Fractional Anisotropy0.3CVR (% MR / mmHg)0.050.20 10 20Body Weight (kg)0.000 10 20Body Weight (kg)Figure 2. Observed FA (a) and CVR (b) changes during pig braindevelopment. The red line represents a log-linear fit to the data points.45 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong><strong>Imaging</strong> features <strong>of</strong> anterior pyriform aperture stenosisand central incisor syndrome including labyrinthine dysplasiaJohanna Monsalve MD 1 , Helen M. Branson MD 1 ,Blake Papsin MD 2 , Grace Yoon 3 , Susan Blaser MD 1,21 <strong>Department</strong> <strong>of</strong> Diagnostic <strong>Imaging</strong>, Division <strong>of</strong> Pediatric Neuroradiology2 <strong>Department</strong> <strong>of</strong> Paediatric Otolaryngology/Head and Neck Surgery3 <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> GeneticsThe Hospital for Sick Children and University <strong>of</strong> Toronto, Toronto, Ontario, CanadaBackground and Purpose: Congenital pyriform aperture stenosis (CPAS) is an unusual,but well described cause <strong>of</strong> nasal obstruction, usually in the newborn. CPAS isfrequently associated with single central mega-incisor. Reported CNS features includemidline anomalies such as holoprosencephaly and posterior pituitary ectopia. Otherassociations include midface hypoplasia, triangular shaped palate with midline ridge andseveral multiple congenital anomaly syndromes, including VACTERL, CHARGE and22q11DS. We describe the imaging features in 33 cases and present several new findingsand associations, such as crowding <strong>of</strong> the maxillary dentition and labyrinthine dysplasia.Materials and Methods: We retrospectively reviewed imaging characteristics <strong>of</strong> 33patients with a diagnosis <strong>of</strong> CPAS during the period 1993 to 2008 (16 years).Results: A total <strong>of</strong> 33 patient with CPAS were identified. There were 16 males and 17females. Eighteen patients underwent both CT and MRI (including one fetus), 8 patientsunderwent CT and 7 patients (including an additional fetus) had only MRI performed.Important findings included: superior central megaincisor (SCMI) in 23/33 (69.7%) ,crowding <strong>of</strong> the lateral incisors when SCMI was not present in 10/33 (30.3%), narrowednasal pyriform aperture (NPA): 3.9 - 12.1 mm in 32/33, triangular palate in 31/33 (94%)and a midline palatal ridge in 32/33 (97%). Even when SCMI was present, there wascrowding <strong>of</strong> the remainder <strong>of</strong> teeth in the triangular shaped palate. Typical features <strong>of</strong>PPE in 5/33 (15%) and holoprosencephaly in 4/33 (12% ) were also identified.We also describe dysplasia <strong>of</strong> the horizontal semicircular canal in 25% <strong>of</strong> 64 ears.Additional inner ear anomalies included enlarged vestibular aqueduct, small cochlearnerve canal, enlarged vestibule and stenotic internal auditory canal in several patients.Conclusion: New features <strong>of</strong> CPAS include inner ear dysplasia and crowding <strong>of</strong> thelateral incisors in patients with two central maxillary incisors, when SCMI was notpresent.46 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>MRI imaging assessment <strong>of</strong> parapharyngeal extensionin nasopharyngeal carcinomaA Bharatha, E Yu, AL Thompson, TD Walters, ES BartlettPrincess Margaret Hospital, University <strong>of</strong> TorontoPurpose: Nasopharyngeal carcinoma (NPC) <strong>has</strong> a tendency for early parapharyngealextension (PPE). As part <strong>of</strong> the current American Joint Committee on Cancer (AJCC-TNM) staging <strong>of</strong> NPC, the presence <strong>of</strong> PPE differentiates T1/T2a from T2b disease, andis associated with worse prognosis. However, the radiologic definition <strong>of</strong> PPE lacksconsensus. The AJCC staging system defines PPE as tumor extension posterolateral tothe pharyngobasilar fascia (PBF). The purpose <strong>of</strong> this study is: 1.) to determine whetherPPE can be reliably assessed by different readers; 2.) to evaluate several potentialindicators <strong>of</strong> PPE; and, 3.) to highlight potential issues in the current AJCC stagingdefinition <strong>of</strong> PPE.Materials and Methods: Initial staging MR studies from 50 consecutive pre-treatmentNPC patients were identified. The nasopharyngeal/parapharyngeal tissues were separatedinto right/left sides and assessed separately. Three radiologists independently reviewedeach side in a randomized blinded fashion for the presence <strong>of</strong> PPE based on the AJCCstaging definition. PPE's relationship to 1.) presence <strong>of</strong> pharyngobasilar fascia attenuationor disruption; and 2.) tumor extension beyond a previously described "line" joining themedial pterygoid plate and the lateral ICA was evaluated. In addition, we also examinedthe relationship <strong>of</strong> the AJCC PPE definition to tumor involvement <strong>of</strong> six structuresadjacent to the PBF [1. levator veli palatini (LvP); 2. tensor veli palatini (TvP);3. neurovascular bundle (NVB); 4. prestyloid parapharyngeal fat (PsF); 5. prevertebralmusculature (PvM); and 6. pterygoid process marrow signal change (PtM). Data werecompared using the Kappa statistic and McNemar's Test.Results: Tumor was present in 83/100 sides, with PPE present in 47 (57%). There wasgood inter- and intra-observer agreement for PPE. In normal sides, the PBF was alwaysdetected. Attenuation or disruption <strong>of</strong> the PBF was a very good proxy for PPE(Sensitivity 99%, Specificity 94%, kappa 0.95, p
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>improved by incorporating more specific reference to standard radiologic spaces andlandmarks.Table 1: Relationship <strong>of</strong> PPE cases (n=47) to tumor involvement <strong>of</strong> six structuresadjacent to the PBFLvP TvP NVB PsF PvM PtMn 22 10 22 5 36 17% 47 21 47 11 77 3648 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Vascular andInterventional <strong>Imaging</strong>49 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Short-term outcomes after varicocele repair by embolizationand microsurgical varicocelectomy: Implications for IVF planningJR Beecr<strong>of</strong>t, A Mujoomdar, G Patry, KC Lo, JR Kachura, K Jarvi, DK RajanPurpose: To compare short term outcomes on sperm parameters following surgicalversus embolization varicocelectomy.Materials & Methods: A retrospective analysis <strong>of</strong>patients (pts) was performed following varicocele repair surgically via microsurgicalinguinal varicocelectomy (Sx) or by embolization (Emb). Semen analysis (S/A) prior totreatment and at 3 and 6 months following repair were evaluated. Primary outcome waschange in the total motile sperm count (TMC= ejaculate volume x concentration <strong>of</strong> spermx motile fraction). Comparison within and between treatment groups at baseline, 3 and 6-months following treatment was performed using paired and independent T-tests.Results: 56 pts initially evaluated, 28 were in each group. See Table 1 for S/A resultsand results <strong>of</strong> comparisons within treatment groups. Baseline S/A was comparable inboth groups, p=0.92. At 3 months there was a significant improvement in TMC in theEmb group compared to baseline (p=0.036) but not in the Sx group (p=0.45).Importantly, at 3 months 4 patients who initially were oligospermic became azoospermicin the Sx group (14.3%) compared to none in the Emb group. There was a significantdifference in TMC between Emb and Sx groups at 3 months (p=0.04) but not at 6 months(p=0.27).Conclusion: Embolization <strong>of</strong>fers better short-term outcomes (3-months) versusmicrosurgical varicocelectomy. By 6 months both the Emb and Sx groups had similarimprovements in TMC. Delayed improvement following Sx may be explained bytransient stress to the testis due to anesthesia and surgical procedure itself. These findingsshould be considered among couples planning IVF close to the time <strong>of</strong> varicocele repair.Table 1: Results TMC, comparison within and between Rx groupsTMC ± SD (millions) at % Increase ± SD at P value vs baseline atBaseline 3 mnths 6 mnths 3 mnths 6 mnths 3 mnths 6 mnthsEmb 12.1 ± 23(n=28)Sx 11.6 ± 15(n=28)20.7 ± 20(n=24)10.4 ±15(n=27)20.2 ± 25(n=23)13.5 ± 15(n=26)P value 0.92 0.04 0.20301 ± 582 285 ± 701 0.02 0.05881 ± 288. 85 ± 208 0.22 0.0250 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Interim results <strong>of</strong> the Celect IVC filter registryMark Otto Baerlocher 1 , Murray R Asch 2 , Andy Myers 2 ,Vincent L Oliva 3 , Gilles Soulez 3 , Deborah van Londen 21 Radiology Residency Training Program, University <strong>of</strong> Toronto, Toronto, Ontario2Diagnostic <strong>Imaging</strong>, Lakeridge Health Corporation, Oshawa, Ontario3 Dept de Radiologie, CHUM-Notre-Dame, Montréal, QuébecPurpose: To present interim results <strong>of</strong> the Canadian Celect TM Inferior Vena Cava FilterRegistry.Materials and Methods: A prospective multi-centre registry using standardized dataforms was created in order to determine the safety and ease-<strong>of</strong>-retrieval <strong>of</strong> Cook Inc.’sCelect TM IVC filter .Results: Filters were successfully placed in 40 patients, 58% with deep venousthrombosis and 40% with pulmonary embolic disease (53% male, 47% female; averageage 60.3 years +/- 17.7). 65% <strong>of</strong> patients had a temporary contra-indication to anticoagulation.95% <strong>of</strong> filters were placed infra-renally, and 5% were placed supra-renally.33% were tilted upon placement. 38% <strong>of</strong> patients died <strong>of</strong> unrelated causes prior toplanned filter retrieval. Filter retrieval was attempted in 53% <strong>of</strong> patients; <strong>of</strong> retrievalsattempted, 1 (4%) failed due to orientation <strong>of</strong> the retrieval hook. The most commonreason that retrieval was not attempted was patient death prior to retrieval attempt (83%).Among those with successful retrieval, the average implantation time was 145 days (+/-149 days; range 5-551 days). Cranial/Caudal filter migration and caval penetrationoccurred in 22% and 14% <strong>of</strong> patients respectively. Filter tilt occurred in 45% <strong>of</strong> patients.The mean fluoroscopy time during retrieval was 9.0 min +/-16.6 min (5.7 +/- 3.3 minwith smallest and largest values removed). Radiologists performing the procedures rateddifficulty in filter retrieval as “None” or “Minimal” in 82% <strong>of</strong> patients. There was noevidence <strong>of</strong> filter fracture in any <strong>of</strong> the cases with successful filter removal.Conclusions: Preliminary results demonstrate the Celect TMtechnically easy to retrieve.filter to be safe and51 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Vascular and non-vascular mimics <strong>of</strong> the CT angiography “spot sign”in patients with secondary intracerebral hemorrhageClare Bent, Kong Teng Tan, Dheeraj Rajan, Martin Simons,John Kachura, Kenneth SnidermanPurpose: Unfavorable proximal aortic neck morphology may predispose to an increasedincidence <strong>of</strong> acute and delayed adverse events after endovascular aortic repair (EVAR).With increasing technical expertise and newer stent-graft design, a greater proportion <strong>of</strong>patients with unfavorable neck anatomy are being <strong>of</strong>fered EVAR. Supra renal fixationEVAR aims to counter adverse neck anatomy and provide secure proximal fixation andsealing. The objective <strong>of</strong> this study is to evaluate clinical outcomes following supra renalfixation EVAR.Materials & Methods: Between October 2005 and September 2008, 114 supra renalfixation EVAR procedures (77 Cook consisting <strong>of</strong> 17 Zenith and 60 Zenith ‘FLEX’; 37Medtronic Talent) were performed. Procedural data were collected prospectively andsupplemented with retrospective review <strong>of</strong> electronic patient records and radiologicalimages. Aortic morphology was assessed using computed tomographic angiography (CTA).Patients were classified as having unfavorable proximal aortic neck anatomy by thefollowing criteria: proximal aortic neck diameter >30mm, neck length 60°, conical neck configuration and circumferential thrombus >50%. Clinical outcomes in45 patients with zero adverse features (non hostile necks) were compared with 69 patientswith one or more adverse features (hostile necks). Mean follow up was 17.8 ± 8.2 months(range: 0.75-39 months).Results: Of 69 patients classified as having a hostile proximal aortic neck, 11 patients hada neck diameter <strong>of</strong> >30mm (mean: 32.1 ± 1.4mm), 33 patients a short neck (mean length:10.7 ± 2.2mm), 37 patients a markedly angulated neck (mean angle: 70.8 ± 9.6°), 25patients a conical aortic neck and 2 patients had circumferential thrombus <strong>of</strong> >50%.Twenty-nine patients (42.0%) demonstrated more than one unfavorable anatomical feature.During comparison <strong>of</strong> the non hostile neck with the hostile neck group, there were nosignificant differences in the incidence <strong>of</strong> primary technical success (p=1.0), assistedprimary technical success (p=1.0), intra-operative adjunctive procedures (p=1.0), earlyproximal type I endoleak (30 days)(p=1.0), distal type I endoleak (p=0.15), type II endoleak (p=0.45), type III endoleak(p=1.0), secondary interventions (p=1.0), aneurysm sac expansion (p=1.0), or 30 daymortality (p=1.0). No association was demonstrated between the number <strong>of</strong> hostilecharacteristics or degree <strong>of</strong> angulation with adverse outcome. Multivariate logisticregression identified no correlation between clinical outcome and the presence <strong>of</strong> eachhostile neck characteristic.Conclusion: Patients with hostile proximal aortic neck anatomy may be treated with suprarenal fixation EVAR. Early and midterm clinical outcomes are promising. ‘Instruction foruse’ guidelines may be expanded to include patients with hostile proximal aortic neckanatomy.52 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Assessment <strong>of</strong> clinical predictors for endoleaks and complications in patientsundergoing endovascular aneurysm repair (EVAR)Del Dhanoa, Vikram PrabhudesaiIntroduction: During recent years there <strong>has</strong> <strong>been</strong> a shift <strong>of</strong> thoracic and abdominalaneurysm management from an open repair in the operating theatre to an endovascularaneurysm repair (EVAR) (1). This trend is due to the decreases in mortality,postoperative complications and hospital length <strong>of</strong> stay seen in patients who are treatedusing the endovascular approach (2, 3). EVAR is becoming a new standard for thoracicand abdominal aneurysm repair but the procedure is still relatively new and evolving.Practitioners <strong>of</strong> EVAR should be cognizant <strong>of</strong> endoleak and complication rates as theyimprove their EVAR practice over time. Part <strong>of</strong> the strategy to decrease endoleaks andcomplications is to identify preoperative clinical features that may increase theprobability <strong>of</strong> EVAR endoleaks and complications. The purpose <strong>of</strong> this study is toidentify patient demographic features as well as preoperative co-morbidities that maylead to an increase in peri- and postoperative EVAR complications.Objective: To define the preoperative clinical characteristics that identify patients atincreased risk for peri- and postoperative endovascular aneurysm repair (EVAR)endoleaks and complications.Materials and Methods: 114 EVAR patients were retrospectively evaluated over a 10year period (1998-2007). Sources <strong>of</strong> patient information include demographic data,clinical features, preoperative vascular surgery and anaesthesia consults, operative notes,and postoperative follow-up progress notes. Different demographic parameters wereanalyzed (including age, gender, type <strong>of</strong> aneurysm) as well as patient comorbidities (suc<strong>has</strong> diabetes, coronary artery disease (CAD), cerebrovascular accidents (CVA), chronicobstructive lung disease (COPD)) to determine if there was a difference betweencomplication rates with respect to each clinical feature.Measurements and Results: The mean age <strong>of</strong> the patients being studied was 72.5 yearsold consisting <strong>of</strong> 102 males (89.5%) and 12 females (10.5%).There were 21 endoleaks <strong>of</strong> which 4 were type 1 (18%) and 18 were type 2 (82%) and 8occurred within the first 30 days (36%). The rates <strong>of</strong> endoleak by year were 31% between1998-2004, 26.9% for 2005, 13.5% for 2006, 14.3% for 2007 with a total endoleak rate<strong>of</strong> 19.3% over a 10 year period. There was no statistical significance <strong>of</strong> endoleakoccurrence between years (p-value=0.28).The complication rates by year were 12.5% between 1998-2004, 11.5% for 2005, 21.6%for 2006, 11.4% for 2007 with a total complication rate <strong>of</strong> 14.9% over a 10 year period.There was no statistical significance <strong>of</strong> complication occurrence between time intervals(p-value=0.58). Early complications, defined as less than 30 days from the date <strong>of</strong> theprocedure, were quantified as 7%. The 30 day all-cause mortality rate was 0.9%. The53 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>complications were wound infections (5.3%), myocardial infarctions (2.6%), graftocclusion (1.8%), graft migration (0.9%), ischemic stroke (0.9%), contrast inducednephropathy (0.9%), spinal cord infarct (0.9%), heparin induced thrombocytopenia(0.9%) and pneumonia (0.9%).Complication rates by preoperative clinical feature was 11.5% in 52 smokers versus 18%in 62 non-smokers (p-value=0.33), 13.3% in 15 diabetics versus 15.2% in 99 nondiabetics(p-value=0.85), 8.3% in 12 renal insufficiency patients versus 15.8% in 101non-renal insufficiency patients (p-value=0.5), 15% in 60 CAD patient versus 15.1% in53 non-CAD patients (p-value=0.99), 14.3% in 14 CVA patients versus 15.2% in 99 non-CVA patients (p-value=0.93), 22.7% in 22 cancer patients versus 13.2% in 91 non-cancerpatients (p-value=0.27) and 8.7% in 23 COPD patients versus 16.7% in 90 non-COPD(p-value=0.35). There was no statistical significance between endoleak or complicationrates and respective preoperative co-morbid clinical feature.Conclusion: We conclude that among patients undergoing EVAR repair endoleakoccurrence and postoperative complications cannot be predicted by the presence <strong>of</strong>readily identifiable preoperative clinical characteristics.References:1. TF Lindsay. Canadian Society for Vascular Surgery consensus statement onendovascular aneurysm repair. Canadian <strong>Medical</strong> Association Journal. 2005 March29:172 (7).2. F Aarts, S van Sterkenburg, JD Blankensteijn. Endovascular aneurysm repair versusopen aneurysm repair: Comparison <strong>of</strong> treatment outcome and procedure-relatedreintervention rate. Annals <strong>of</strong> Vascular Surgery. 2005 Sept;19(5), 699-704.3. WA Lee, JW Carter, G Upchurch, JM Seeger, TS Huber. Perioperative outcomesafter open and endovascular repair <strong>of</strong> intact abdominal aortic aneurysms in the UnitedStates during 2001. Journal <strong>of</strong> Vascular Surgery. 2004 Mar;39(3):491-6.54 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Combined prophylactic internal iliac artery balloon occlusion anduterine artery embolization in the management <strong>of</strong> invasive placentaDonna L. D'Souza 1 , John R. Kachura 1 , Rob Beecr<strong>of</strong>t 1 ,Rory C. Windrim 2 , John C. Kingdom 21 Interventional Radiology, Mount Sinai Hospital, Toronto, ON2 Obstetrics, Mount Sinai Hospital, Toronto, ONPurpose: To evaluate the safety and efficacy <strong>of</strong> combined intra-operative internal iliacartery balloon occlusion and post-operative uterine artery embolization in patients withinvasive placenta undergoing caesarean delivery.Materials and Methods: Between 2002 and 2008, 14 patients with invasive placentaunderwent pre-operative prophylactic insertion <strong>of</strong> bilateral internal iliac artery occlusionballoons, intra-operative inflation <strong>of</strong> the balloons, and post-operative bilateral uterineartery embolization using absorbable gelatin sponge. All patients had concomitantplacenta previa, were multiparous, and 93% had previous caesarean section. Invasiveplacenta was confirmed by pre-delivery MRI (8 had placenta percreta and 6 had placentaincreta). Via retrospective chart review, the following outcomes were evaluated: intraoperativeblood loss, transfusion requirement, hysterectomy rate, major complicationsand fluoroscopy time. Major complications were defined as those requiring furtherendovascular or surgical intervention.Results: All patients in the study group (n=14) underwent caesarean section: 2 patientsunderwent planned caesarean hysterectomy and 12 patients were planned for uterinepreservation. Mean maternal age was 34 years (range 23-39), and mean gestational age atdelivery was 35 weeks (range 30-38). Mean fluoroscopy time for pre-delivery ballooninsertion was 5.4 minutes (range 2.0-16.5), and for post-operative embolization was 10.6minutes (range 3.3-15.9). The mean estimated intra-operative blood loss was 1250 mL(range 400-4000). 4/14 (28.6%) patients required a blood transfusion with mean volume<strong>of</strong> 2.25 units packed red blood cells (range 1-4). There were no major complications inthe 2 patients who had planned caesarean hysterectomy. Within the group planned foruterine preservation, 5/12 (36%) had a major complication: post-partum hemorrhage(5/5), DIC (2/5) and endomyometritis (2/5). 4 <strong>of</strong> these patients required hysterectomy tocontrol the post-partum hemorrhage. The hysterectomy rate in the uterine preservationgroup was therefore 33% (4/12), and successful uterine preservation was achieved in67% (8/12).Conclusion: The use <strong>of</strong> combined prophylactic bilateral internal iliac artery balloonocclusion and uterine artery embolization is safe and effective in controlling intraoperativeblood loss and preserving the uterus in patients with invasive placentaundergoing caesarean delivery.55 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Molecular imaging <strong>of</strong> atherosclerotic plaqueKT Tan, SG Pasian, J Zhan, S Chiu, G Leung, AR MoodyBackground: The imaging <strong>of</strong> atherosclerosis <strong>has</strong>, up until the past few years, <strong>been</strong>limited to the study <strong>of</strong> luminal size. Recently, there <strong>has</strong> <strong>been</strong> an interest in the description<strong>of</strong> plaque morphology/ constituents. However, macroscopic changes are always precededby changes in the molecular expression <strong>of</strong> various molecules. Vascular cell adhesionmolecule-1 (VCAM-1) is an adhesion molecule that is upregulated in atherosclerosis andplays an important role in atherogenesis. The long term goal <strong>of</strong> our group is to synthesiseultrasound and MRI contrast agents that can detect VCAM-1 expression in vivo in arabbit model <strong>of</strong> atherosclerosis.Hypotheses(1) VCAM-1 is expressed in our rabbit model <strong>of</strong> atherosclerosis.(2) A VCAM-1 antibody binding microbubble contrast agent can be synthesized inour laboratory.(3) An anti-VCAM-1 targeted iron oxide particle can be imaged ex vivo using MRI.Methods: Aortic arch segments from a rabbit model <strong>of</strong> atherosclerosis are studiedhistologically for the expression <strong>of</strong> VCAM-1. For ultrasound imaging, perflurobutane isencased in a phospholipid-polyethylene glycol shell to form a microbubble. An antibodydirected against VCAM-1 is then attached to the microbubble.The same anti-VCAM-1 antibody can also be attached to iron oxide particles. TheVCAM-1 targeted iron oxide particle is then used to perfuse an ex vivo rabbit aortic archprior to MR imaging. Histological confirmation <strong>of</strong> iron oxide staining will be obtained.Results: Histological examination <strong>has</strong> confirmed the presence <strong>of</strong> VCAM-1 expression inthe aorta <strong>of</strong> our rabbit model <strong>of</strong> atherosclerosis. VCAM-1 can be found in both theluminal and neovascular endothelium. There is also VCAM-1 expression by vascularsmooth muscle cells.Preliminary ex-vivo results from using the VCAM-1 targeted iron oxide particles in theMRI scanner suggest that they are capable <strong>of</strong> detecting VCAM-1 expression in rabbitaortic arch. Histological confirmation is pending.An anti-VCAM-1 antibody binding microbubble <strong>has</strong> <strong>been</strong> synthesized in our department.This <strong>has</strong> <strong>been</strong> confirmed by both flow cytometry and microscopy.Conclusions: Although in its early stages, this work suggests that the MR imaging <strong>of</strong>VCAM-1 expression is feasible. We will be doing further studies using cell culture todetermine the optimal binding conditions for the targeted iron oxide particle.The results from the ultrasound contrast experiments are promising. At present, we are inthe process <strong>of</strong> fine tuning our contrast agent, in order to obtain microbubbles <strong>of</strong> uniformsize. Further in vitro work using cell culture is also planned to study the interactionbetween the targeted microbubble with endothelial cells.56 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Radi<strong>of</strong>requency ablation <strong>of</strong> renal cell carcinoma: Mid-term resultsJohn R. KachuraDivision <strong>of</strong> Vascular and Interventional Radiology, <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong>,University Health Network and Mount Sinai Hospital, University <strong>of</strong> TorontoPurpose: To evaluate the mid-term efficacy and safety <strong>of</strong> radi<strong>of</strong>requency ablation (RFA)<strong>of</strong> renal cell carcinoma (RCC).Materials and Methods: The medical records and imaging <strong>of</strong> all patients with RCCtreated with RFA from January 1, 2004 to December 31, 2008 were reviewed. Thepatient cohort consisted <strong>of</strong> 75 patients (57 male, 18 female) with a mean age <strong>of</strong> 61 years(range 28-89 years). Each patient had an outpatient percutaneous RFA procedure undercombined ultrasound and CT guidance with conscious sedation using a 3.5 cm or 4 cmarray multi-tined expandable LeVeen electrode. All patients except one had significantcomorbidities (n=60), renal dysfunction (n=28), previous nephrectomy (n=8), and/or vonHippel Lindau syndrome (n=9). In total, 81 tumors were ablated with a mean size <strong>of</strong> 2.8cm (range 1.0-7.4 cm). More than 80% <strong>of</strong> tumors were pathologically proven to be RCC.Successful ablation was defined as no tumor enhancement and no growth on follow-upcontrast-enhanced CT, MRI, and/or US.Results: Mean follow-up was 27 months (range 1-58 months). Successful ablation wasnoted in 73 <strong>of</strong> the 75 patients after a single RFA procedure (primary treatmenteffectiveness = 97%). One <strong>of</strong> the 2 patients with residual viable tumor was successfullyablated after a second RFA procedure using a Cool-tip straight needle electrode(secondary treatment effectiveness = 99%). Recurrent viable tumor after successfulablation <strong>has</strong> not <strong>been</strong> encountered thus far, but 2 patients developed enhancing s<strong>of</strong>t tissueat the ablation zone pathologically proven to represent inflammation. There were 4 majorcomplications (one abscess, 3 ureteral strictures) and 3 minor complications (one splenichematoma, 2 patients with leg pain from psoas injury despite thermal protection with airor dextrose). One patient’s renal dysfunction continued to worsen at an unchanged rate,eventually requiring dialysis.Conclusions: Mid-term results show that RFA <strong>of</strong> RCC using a multi-tined expandableelectrode is a safe and effective one-time outpatient procedure performed without generalanesthesia. Long-term follow-up is required before considering RFA <strong>of</strong> RCC in patientswho are candidates for surgical resection.57 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Bland hepatic artery embolization for symptomaticneuroendocrine tumor metastases: An 11-year experienceKebby F.G. King, John R. KachuraPurpose: To evaluate the safety and efficacy <strong>of</strong> bland hepatic artery embolization for thepalliation <strong>of</strong> symptomatic neuroendocrine tumor metastases, and to assess radiologicresponse.Materials and Methods: Between 1998 and <strong>2009</strong>, 50 hepatic artery embolizationprocedures using polyvinyl alcohol particles or tris-acryl gelatin microspheres wereperformed at 2 hospitals for 28 patients with unresectable, biopsy-confirmed hepaticmetastases from carcinoid or neuroendocrine tumors. A retrospective review wasperformed to evaluate symptomatic response, major complications, and radiologicresponse. Radiologic assessment was performed using RECIST and EASL criteria.Results: The patient cohort consisted <strong>of</strong> 15 females and 13 males, with a mean age <strong>of</strong> 61years (range 37-79). Indications for embolization included abdominal pain and distention(n= 18), flushing and/or other hormonal symptoms (n=5), fatigue (n=4), and rapid tumorprogression (n=1). Mean clinical follow-up was 25 months (range 0.5-69). Of the 27patients for whom clinical follow-up information was available, 19 patients experiencedsignificant symptomatic improvement (70%). There were no treatment-related deaths.Major complications occurred in 4 patients: 2 had sepsis, one had a large hematoma, andone had encephalopathy for which no etiology was found.Using RECIST criteria, no progression was noted after 35 procedures (35/48= 73%). Ofthese, partial response was seen after 14 and stable disease after 21 procedures.Progressive disease was noted after 13 procedures (13/48= 27%). The mean time toprogression was 13 months (range 0-23).EASL necrosis criteria were used to quantify necrosis. 0%, less than 50%, greater than50% and 100% necrosis was seen initially after 3, 14, 14, and 15 procedures (7%, 30%,30%, 33%) respectively. No increase in enhancement throughout follow-up was notedafter 22 procedures (22/46 =48%). The mean length <strong>of</strong> time to show increasedenhancement from the initial post-embolization CT was 8 months (range 1-25).After 11 <strong>of</strong> the 50 embolization procedures, an initial increase in tumor size was noted,but with 6 <strong>of</strong> these 11 cases (55%) there was greater than 50% necrosis.Conclusions: Bland hepatic artery embolization for neuroendocrine tumor metastases issafe and effective for the palliation <strong>of</strong> symptoms. Most patients demonstrated radiologicstability or improvement that persisted on average for 13 months, when using sizecriteria. In a minority <strong>of</strong> patients, size criteria were discordant with response as measuredby tumor necrosis.58 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Efficacy <strong>of</strong> stent-graft placement for salvage <strong>of</strong>dysfunctional hemodialysis fistulasD.K. Rajan, C.L. Bent, M. Simons, K. Tan, R. Beecr<strong>of</strong>t,J. Jaskolka, J. Kachura, K. SnidermanUniversity Health Network, University <strong>of</strong> TorontoPurpose: To retrospectively determine the clinical efficacy <strong>of</strong> stent-graft placement forsalvage <strong>of</strong> dysfunctional autogenous hemodialysis fistulas.Material and Methods: Between September 2006 and June 2008, 24 Fluency stentgrafts(Cr Bard, Tempe, AZ) were inserted in 17 patients (12 men and 5 women; meanage: 67 years, range 25 - 85 years) with failing autogenous hemodialysis fistulas (tworadiocephalic, 12 brachiocephalic and three brachiobasilic). Six fistulas were thrombosedat presentation. Indications for stent-graft insertion included: one venous occlusion, 9resistant stenoses, six pseudoaneurysms and one rupture following fistuloplasty. Fistulafunction pre and post intervention was assessed using ultrasound dilution technique.Results: Of the 17 fistulas intervened on, 9 were considered unsalvageablepercutaneously. Initial technical success was 100%. Clinical success was 100%. Theprimary patency rates at 3, 6 and 12 months were 94.1%, 88.2% and 64.7% respectively.With the Kaplan-Meier method, the primary patency rates with standard errors <strong>of</strong> theestimate at 3 and 6 months were 94% (0.82 - 1.06), and at 12 months, 94% (0.79 - 1.08).Secondary patency rates were equal to primary patency rates. No accesses were lost andno patients were lost to follow up over the study period. The binary re-stenosis rate at 6months was 5.9%. The percentage <strong>of</strong> fistulas with concurrent lesions treated at the time<strong>of</strong> stent-graft placement was 41.2%. The mean transonic flow rate prior to interventionwas 959.3 ml/min. Post intervention was 2186.8 ml/min (p=0.01). No complicationsoccurred associated with stent-graft deployment.Conclusion: Stent-graft placement in dysfunctional autogenous fistulas, some <strong>of</strong> whichwere considered unsalvageable with traditional percutaneous methods is technicallyfeasible. Stent-graft placement was effective in preserving function and preventing accessabandonment with patency rates that exceed historical patencies with angioplasty and/oruncovered stents.59 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Retrospective review <strong>of</strong> non-vascular findings in peripheral CT angiographyAhmed Farooq, Jeff JaskolkaObjectives: The purpose <strong>of</strong> this study was to evaluate the incidence and significance <strong>of</strong>extravascular findings in patients undergoing CT angiography (CTA) <strong>of</strong> the abdomen,pelvis and lower extremities.Methods: A retrospective review <strong>of</strong> patients examined between March 2006 and Aug2008 was performed. Patients underwent either CTA <strong>of</strong> the abdomen and pelvis alone orCTA <strong>of</strong> the abdomen, pelvis and lower extremities. Images where reviewed by a boardcertified radiologist and all extravascular findings recorded and compared with thecorresponding dictated radiologist reports. Extravascular findings were divided into 3categories: incidental, clinically important but probably benign, and serious/suspicious.The patients’ electronic medical records and radiology reports were reviewed todetermine the impact <strong>of</strong> these findings on patient management and the outcome <strong>of</strong> anyfollow-up imaging studies or other diagnostic evaluation.Results: A total <strong>of</strong> 76 patients were imaged in the study period, <strong>of</strong> which 52 were male(68.4%). 70% <strong>of</strong> patients showed extravascular findings. Of these, 46 patients (61%)had incidental findings, 10 (13%) had clinically significant but probably benign findingsand 5 (7%) had serious/suspicious findings. In the patients with serious/suspiciousfindings, 2 were confirmed to have neoplastic disease on follow up imaging whilemalignancy was ruled out in the other 3 patients. All significant findings were seen in theabdomen or pelvis rather than the images <strong>of</strong> the extremities. <strong>Imaging</strong> findings in theretrospective review were concordant with the patients’ dictated reports in all cases.Conclusion: CTA is a useful tool in assessing vascular disease, however CTA <strong>of</strong> theabdomen can also uncover a significant number <strong>of</strong> extravascular findings. Almost 20% <strong>of</strong>incidental findings were clinically significant or resulted in a serious diagnosis such asneoplasm requiring further treatment. Proper review <strong>of</strong> all images in a CTA examinationis important for the detection <strong>of</strong> these abnormalities to ensure patients can receiveappropriate diagnostic workup or treatment.60 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Limb perfusion: Characterization <strong>of</strong> a new techniqueJoe Barfett, Edmund Ng, Jeff JaskolkaPurpose: In patients with critical limb ischemia, wound and ulcer healing are dependentupon adequate blood flow. The goal <strong>of</strong> this study was to quantify skeletal muscleperfusion in the feet <strong>of</strong> normal subjects with dynamic perfusion CT, taking advantage <strong>of</strong>the 16cm scan range <strong>of</strong> the Toshiba Aquilon One TM 320-multidetector scanner.Materials and Methods: 6 healthy male subjects, aged 22-50, were enrolled in thestudy. Dynamic CT was performed from the ankle to the plantar aspect <strong>of</strong> the foot afterbolus injection <strong>of</strong> intravenous contrast at 5mL/sec. Contrast transit to the ankle wasdetermined with a timing bolus <strong>of</strong> 20mL, injected at 5mL/sec. Restraints were used inthe later patients to reduce motion artifact. IV contrast dose was varied between 50-90mLand radiation dose varied from low (~2.7mSv total dose) to standard (~4.4mSv) for thetotal exam. Several acquisition protocols were tested. Perfusion analysis was performedusing both deconvolution by single value decomposition on a commercial workstationand calculation <strong>of</strong> perfusion index by a compartmental model with custom s<strong>of</strong>tware.Results: Each foot was analyzed separately, giving 12 datasets. Beam hardening artifactlimited evaluation <strong>of</strong> the time density curve in patients one to four, scanned using the lowradiation dose protocol and lower contrast volumes <strong>of</strong> 50 and 70mL. Perfusion index wascalculated with a variation <strong>of</strong> the Mullani-Gould formula in patients five and six in themuscles <strong>of</strong> the plantar compartment, plantar fat and bone <strong>of</strong> the distal tibial epiphysisafter standard dose CT and 90mL <strong>of</strong> contrast. Analysis <strong>of</strong> the entire plantar compartmenten bloc with compartmental analysis was more efficacious than individual voxel timedensity analysis by deconvolution. Perfusion index estimates ranged between 0.17 and1.01 /s in the muscular compartment. The use <strong>of</strong> restraints reduced patient motion andfacilitated analysis.Conclusion: Beam hardening artifacts associated with low radiation and contrast doseprotocols, as well as low contrast uptake in muscle in general, limit reliable estimation <strong>of</strong>s<strong>of</strong>t tissue enhancement. Dynamic acquisitions with serial CT examinations <strong>of</strong> normalradiation dose are needed to perform quantification <strong>of</strong> muscle perfusion, and injection <strong>of</strong>90mL <strong>of</strong> iodinated contrast allows estimation <strong>of</strong> Perfusion Index in the plantarcompartment. We are now undertaking a larger study with these optimized parameters.61 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Abdominal, GU, and GI<strong>Imaging</strong>62 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>CT urography: Image quality and accuracyfor upper tract urothelial cancerME O’Malley, E Maheshwari, S Ghai, M Staunton, C MasseyDivision <strong>of</strong> Abdominal <strong>Imaging</strong>, Joint <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong>Purpose: To assess the quality and diagnostic accuracy <strong>of</strong> CT urography using a splitbolustechnique.Materials and Methods: We identified 200 consecutive patients (119 men, 81 women;median age 58 years, range, 18 – 89) with a history <strong>of</strong> hematuria who had CTU betweenJanuary 2004 and December 2006. The majority <strong>of</strong> patients were scanned on a 64-sliceCT scanner. CTU protocol included anatomic coverage from top <strong>of</strong> kidneys to bladderbase. The first set <strong>of</strong> images was obtained without IV contrast. Then 50 ml <strong>of</strong> contrastwas injected at 3 ml/sec. Five minutes after injection, an additional 80 ml <strong>of</strong> contrast wasinjected at 3 ml/sec and a second set <strong>of</strong> images was acquired 100 seconds after the secondinjection. Images were displayed in axial (3 x 1.5mm) and coronal (3 x 3mm) planes.Images were independently reviewed by two radiologists blinded to final diagnosis.Upper urinary tracts were divided into 4 segments. To determine quality <strong>of</strong> CTUprotocol, degree <strong>of</strong> opacification <strong>of</strong> each segment was recorded as follows: 0-unopacified, 1- less than 50%, 2- 50 to 99%, and 3- 100%. For diagnostic accuracy <strong>of</strong>upper tract tumors (UTT), each study was subjectively scored as follows: 0 - negative, 1 -probably negative, 2 - indeterminate, 3 - probably abnormal, 4 - definitely abnormal.Standard <strong>of</strong> reference included all clinical and laboratory data up to 12 months followingCTU.Results: For reviewers 1 and 2, 85.1% and 84.5% <strong>of</strong> segments were at least 50%opacified, respectively. For hematuria, the final diagnosis was: no cause, 123 (61.5%);urothelial cancer, 27 (13.5%); nonmalignant 49 (24.5%) and indeterminate 4 (2%)patients. There were 9 UTT. Sensitivity, specificity, and accuracy for UTT forprospective interpretation, reviewer 1, and reviewer 2 were: 88.9, 99.0, 98.5%; 100, 99.5,99.5%; and 88.9, 99.0, 98.5%, respectively.Conclusion: CT urography using a split-bolus technique provided high quality studiesand was accurate for detection <strong>of</strong> UTT.63 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Microbubble DCE-US, DCE-CT, and DCE-MRI imaging for theassessment <strong>of</strong> tumor response to Sunitinib treatment<strong>of</strong> renal cell carcinoma: Preliminary resultsM Atri, D Cheng, PN Burns, G Stanisz, R Williams,G Lueck, J Hudson, C Bailey, G BjarnasonPurpose: To evaluate three imaging modalities; dynamic contrast enhanced-US (DCE-US), dynamic contrast enhanced-CT (DCE-CT), dynamic contrast enhanced-MRI (DCE-MRI) to predict anti-angiogenic response to Sunitinib (Sutent) for treatment <strong>of</strong> metastaticRCC.Materials and Methods: A cohort <strong>of</strong> patients with biopsy proven RCC received Sutentfor 4 weeks. Following the protocol, 13 patients had baseline DCE-US, DCE-CT, DCE-MRI, 11 had DEC-US and DCE-MRI 2 weeks into treatment, 7 had DCE-US, 8 DCE-CTat 4 weeks, and 10 had DCE-US one week post treatment. DCE-US was performed on anIU22 Phillips machine during drip infusion <strong>of</strong> 1.1 ml Definity/50 mL 9% saline usinghigh MI disruption/low MI replenishment, DCE-CT on a 64 slice MDCT using 1 mL/kg<strong>of</strong> Visipaque at 5 mL/s covering 4 cm at 8 x 5 mm collimation, 1 scans/s for 1 minute, 1scans/5s for 1 minute, and DCE-MRI on a 1.5T GE using 0.1 mL/kg Gadodiamide, 3DLAVA, 12 coronal scans at 8 mm slice thickness at 1 scan/5s for 7 minutes. Relativeblood volume was calculated by DCE-US, Blood flow (BF), blood volume (BV),permeability surface area (PS) by DCE-CT, Ktrans (min-1), and Ve (mL) (volume <strong>of</strong> theextra-cellular extra-vascular space) by DCE-MRI.Results: At 2 week into treatment, DCE-US showed 61% drop in BV (p=0.001), DCE-MRI 3.4% drop in Ve (p>0.05), and 53% drop in Ktrans (p=0.03). At 4 weeks intotreatment DCE-US showed 75% drop in BV (p=0.01), DCE-CT 82% drop in BF(p=0.008), 72% drop in BV (p=0.008), and 61% drop in PS (p=0.008). At 1 week posttreatment DCE-US showed 13% drop in BV (p>0.05).Conclusion: Both DCE-US and DCE-CT showed significant drop in BV duringtreatment. Vessel permeability significantly dropped during treatment as shown on PS byDCE-CT and Ktrans on DCE-MRI. DCE-US showed a rebound <strong>of</strong> BV post treatment.64 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Radiology resident on-call productivity during a night shift schedule:A pilot projectDavid Kelton, Ashish Mahajan, Anthony Hanbidge<strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong>, University <strong>of</strong> TorontoPurpose: There is increasing focus on emergency department (ED) patient workflowand safety. This in part due to recent studies examining the impact <strong>of</strong> trainee duty hourson patient and resident safety, as well as recent government initiatives to improve EDpatient wait times in Ontario. The purpose <strong>of</strong> this study is to compare radiology residenton-call productivity during a night shift schedule with current call schedules.Methods: An R1 and R3 resident performed on-call radiology duties within a modifiedschedule. The pilot project schedule included one resident on a weekday (Monday toFriday) block <strong>of</strong> evenings, 5pm-10pm, and the second resident on a weekday block <strong>of</strong>nights, 10pm-8am. This was organized within the current on-call point distributionsystem used at the University <strong>of</strong> Toronto and performed at Sunnybrook Hospital.Primary outcome was time from cross-sectional study (CT, MRI) to preliminary report.Secondary outcome was preliminary report accuracy compared to final report. The R1resident was blinded to study outcomes. The daily on-call total case volume, traumavolume, and ultrasound volumes were recorded to control for potential sources <strong>of</strong> reportdelay. Analysis was performed using an unpaired 2 tailed T-Test.Results: Reporting times at night during the pilot project were 46±31 minutes for allstudies and 66±53 minutes during the regular call schedule (P=0.02). Reporting times forhead CT, body CT, and CTA were 20±11 min, 53±23 min, 73±39 min during the pilotschedule and 45±37 min, 72±47 min, 117±112 min during the regular call schedule.During the pilot project period, there was an average <strong>of</strong> 25 cross-sectional studiesbetween 5pm-8am (range 17-34), with an average <strong>of</strong> 10 studies between the hours <strong>of</strong>10pm-8am (range 4-13). Total cases, ultrasound, and trauma volumes were similarbetween both schedules. Accuracy was high during both call periods.Conclusion: Radiology resident preliminary reporting times for emergency crosssectionalimaging can be significantly decreased using a block-call schedule whilemaintaining high accuracy.65 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Biliary anatomy <strong>of</strong> potential donor for living donorliver transplantation: The utility <strong>of</strong> CT cholangiographyin cases with indeterminate results on MRCPSean E. McSweeney, Tae Kyoung Kim, Hyun-Jung Jang, Korosh KhaliliPurpose: This study is to determine the efficacy <strong>of</strong> CT cholangiography (CTC) forevaluating biliary anatomy in potential donors for living-donor liver transplantation(LDLT) when MRCP is inconclusive.Materials and Methods: Over a 2-year period, contrast-enhanced (Cholografin) CTCwas performed in 41 potential living liver donors who showed inconclusive results onMRCP. Twenty <strong>of</strong> the 41 patients subsequently underwent partial liver donation and wereincluded in this study. Two independent, blinded radiologists retrospectively reviewedboth MRCP and CTC with 1-month interval and documented the types <strong>of</strong> bile ductbranching patterns, diagnostic confidence (3-point scale), and visualization score <strong>of</strong>intrahepatic bile ducts (4-point scale). MRCP and CTC findings were compared with thegold standard <strong>of</strong> intraoperative cholangiography and surgical findings.Results: There were no complications associated with CTC examinations. CTC correctlyclassified the types <strong>of</strong> biliary anatomy in 17/20 (85%) including 7/9 typical branchingtypes and 10/11 anomalous branching types whereas MRCP correctly classified in 14/20(60%) including 5/9 typical branching types and 7/11 anomalous branching types. All 3misclassified cases by CTC were false identification <strong>of</strong> an accessory right intrahepaticduct joining the CBD. CTC showed higher diagnostic confidence (mean, 2.9) than MRCP(mean, 2.1) (P = .002). CTC also showed higher visualization score (mean, 3.9) thanMRCP (mean, 2.6) (P < .001).Conclusions: CTC accurately depicts biliary tract anatomy in LDLT donors and can beeffectively used when MRCP is inconclusive.66 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>The impact in abdominal imaging with the introduction<strong>of</strong> a dedicated emergency CTRicha Mittal, Josée Sarrazin, Alan MoodyPurpose: The need for emergency (ER) radiological examinations is increasing rapidlyas the standard <strong>of</strong> care for patients presenting to the emergency department continues toevolve. Computed tomography (CT) is the main imaging modality to be requested. Thisplaces more pressure and demand on radiology resources. Many institutions haveinstituted a CT scanner dedicated to the ER department; however there have <strong>been</strong> nostudies that have examined the impact <strong>of</strong> this to patient management and radiologyresource utilization. To better understand the trends in emergency imaging, this studyexamines several aspects <strong>of</strong> the abdominal CT examinations completed for patientspresenting to the ER department. The utilization <strong>of</strong> CT was compared before and afterthe introduction <strong>of</strong> a dedicated ER CT scanner.Methods and Materials: All <strong>of</strong> the reports for CTs completed from patients in the ERdepartment at the time <strong>of</strong> referral were examined for a period <strong>of</strong> 6 months before andafter the introduction <strong>of</strong> a dedicated ER CT (which was March 2007). Data was collectedfrom August 1 2006 to January 31 2007 and August 1 2007 to January 31 2008. Datawas compiled from the imaging reports and electronic data records <strong>of</strong> the emergencyvisit. The following data was collected: total number <strong>of</strong> CTs, number <strong>of</strong> CTs that hadfindings concurring with the referring indication, the number <strong>of</strong> patients dischargedhome, admitted or had surgery after imaging, the indication for the imaging, whetherother imaging was performed before or after the CT and any incidental findings. Adatabase was complied in an excel spreadsheet, which was then analyzed utilizing SPSS12.0 s<strong>of</strong>tware (SPSS Inc, Chicago, IL).Results: A total <strong>of</strong> 950 patients received an abdominal CT scan during the study period,referred from the ER department. 484 were male, 266 were female with an average age <strong>of</strong>55 years. The total number <strong>of</strong> CT requests did not significantly change with 507 beforeand 443 after the introduction <strong>of</strong> the dedicated CT scanner (p=0.543). The number <strong>of</strong>CTs which had findings concurring with the referring indication did not significantlychange either going from 42.0 % to 38.4 % (p=0.513). The number <strong>of</strong> patients admittedor undergoing surgery did not significantly change either. The most common indicationfor CT was renal colic in both groups with up to 18.5% <strong>of</strong> all scans completed for thisindication. The number <strong>of</strong> CTs done related to malignancy staging decreased in thesecond group from 16.0 % to 12.2 % (p=0.003). There was no change in the number <strong>of</strong>patients receiving imaging before or after the CT, nor the number <strong>of</strong> incidental findings(p= 0.226 and p=0.0.91 respectively).Conclusion: Due to the increasing volume <strong>of</strong> imaging requested by the ER department,many hospitals have introduced a dedicated ER CT scanner. This study indicates thatthe introduction <strong>of</strong> a dedicated CT scanner for the emergency department does notincrease the number <strong>of</strong> studies requested by the ER department, nor does change thenumber <strong>of</strong> CTs with positive results. As well, non emergency imaging, such asmalignancy staging, <strong>has</strong> decreased in volume, indicating better utilization <strong>of</strong> imaging foremergency patients.67 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Pseudoenhancement within local ablation zone <strong>of</strong> hepatic tumorsdue to nonlinear artifact on contrast-enhanced ultrasoundHojun Yu, Hyun-Jung Jang, Tae Kyoung Kun, Korosh Khalili,Ross Williams, Gord Lueck, Peter BurnsPurpose: Pseudo-enhancement <strong>of</strong> an avascular region on CEUS <strong>of</strong>ten occurs within anechogenic region <strong>of</strong> radi<strong>of</strong>requency ablation (RFA) zone. The purpose <strong>of</strong> this study wasto describe imaging features <strong>of</strong> this artifact and confirm its origin as nonlinear ultrasoundpropagation.Materials and Methods: Twenty-six patients with no tumor recurrence within RFAzones were included. Three radiologists assessed CEUS pseudo-enhancement in thearterial (90 seconds): presence,degree, time to first appearance, progression over time, and location, correspondinggreyscale echo (hypo/iso/hyperechoic) and lesion depth.Results: Fourteen (14/26, 54%) lesions showed pseudo-enhancement on CEUS. All(14/14) <strong>of</strong> them corresponded to the hyperechoic area within the RFA zone on gray-scaleUS and were non-marginal in location. Pseudo-enhancement more frequently occurred indeep lesions (≥5 cm) than superficial lesions (
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Magnetic resonance imaging <strong>of</strong> liver disease inhereditary hemorrhagic telangiectasiaA Moktassi, L Wu, J O'Rourke, ME Faughnan<strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> and <strong>Department</strong> <strong>of</strong> Medicine,St. Michael’s Hospital, University <strong>of</strong> Toronto, CanadaBackground/Aims: To describe findings, including flow quantification, obtained withmagnetic resonance imaging (MRI) <strong>of</strong> the liver in patients with hereditary hemorrhagictelangiectasia (HHT).Methods: MRI was performed in 35 patients [20 females; mean age, 49 years (range,15–75 years)] seen in the HHT Clinic, during a 2-year period. The protocol was designedto retrospectively evaluate the morphologic changes seen in HHT and evaluate flows.The study protocol was approved by our Review Board in accordance with therecommendations <strong>of</strong> the Human <strong>Research</strong> Committee. The presence <strong>of</strong> shunts, hepaticperfusion disorders, telangiectases, other vascular lesions, and flow abnormalities withinthe celiac and hepatic artery were evaluated by two radiologists in consensus.Results: Thirty-one/35 patients (89%) had a definite clinical diagnosis <strong>of</strong> HHT (CuracaoCriteria). Genetic mutation was available in 16/35 (49%). Nine/35 (25%) weresymptomatic <strong>of</strong> hepatic vascular malformations. Hepatic vascular abnormalities werefound in 23/35 (66%) patients. Arteriosystemic shunts were present in 17/35 (49%)patients and arterioportal shunts in 4 <strong>of</strong> 35 (11%). In 17/35 (49%) patients, parenchymalperfusion disorders were detected. Telangiectases were found in 18/35 (51%) patients. In14/35 (41%) patients, large confluent vascular masses were visualised. In 13/33 (39%)patients, the celiac artery flow volume exceeded 2L/min. The flows ranged from 2-7L/min. In 12 <strong>of</strong> 31 patients (39%) the hepatic artery flow volume exceeded 1L/min, withflows ranging from 1-4 L/min.Conclusions: MRI allows for the characterization <strong>of</strong> hepatic involvement in patientswith HHT.69 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>Interval growth <strong>of</strong> focal nodular hyperplasia in the liver on MR imagingJaydeep Halankar, Tae Kyoung Kim, Hyun-Jung Jang,Korosh Khalili, Masoom HaiderPurpose: To determine the incidence <strong>of</strong> interval growth <strong>of</strong> focal nodular hyperplasia(FNH) in the liver.Materials and Methods: The subjects retrospectively included 120 consecutive patientsfor 2 years who were diagnosed to have FNH by characteristic imaging findings on Gd-BOPTA-enhanced MR imaging and had multiple MR examinations separated by over 6months. There were 25 men and 95 women (age range, 18-80 years; mean, 45 years).Images were retrospectively reviewed for interval growth <strong>of</strong> FNH. The maximum size <strong>of</strong>the lesion was measured on axial arterial-p<strong>has</strong>e images <strong>of</strong> the initial and last MRexaminations. An interval increase in diameter over 10% <strong>of</strong> the initial diameter wasconsidered positive growth. The use <strong>of</strong> oral contraceptives was also documented.Results: Eleven <strong>of</strong> 120 patients (9%), comprising 10 female and 1 male, showed aninterval growth for a period ranging from 7 months to 84 months (mean, 29 months). Theinterval change <strong>of</strong> the size ranged from 0.4 to 2.0 cm (mean, 0.8 cm). The percent change<strong>of</strong> the size ranged from 11% to 133% (mean, 49%). Only 2/10 (20%) female patientswith growing FNH and 30/85 (35%) female patients with non-growing FNH had ahistory <strong>of</strong> oral contraceptives intake.Conclusions: Progressively growing liver masses for a long-term imaging follow-upcannot exclude the diagnosis <strong>of</strong> FNH as an interval growth can be seen in 9% <strong>of</strong> cases.70 <strong>of</strong> 71
University <strong>of</strong> Toronto <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong> <strong>Research</strong> <strong>Day</strong> <strong>2009</strong>No significant difference between nuchal translucency (NT) in weeks 11-13 +6<strong>of</strong> singleton pregnancies conceived spontaneously and by IVF/ICSIPM O’Donoghue 1 , BR H<strong>of</strong>fman 2 , LI Bromberg, 2EM Greenblatt 3 KW Fong 1 , A Toi 1 , N Okun 41 <strong>Department</strong> <strong>of</strong> <strong>Medical</strong> <strong>Imaging</strong>, Mount Sinai Hospital and UniversityHealth Network, University <strong>of</strong> Toronto, Toronto, Canada.2 Laboratory Medicine and Pathobiology, University <strong>of</strong> Torontoand Pathology and Laboratory Medicine, Mount Sinai Hospital.3 Reproductive Biology Unit, Mount Sinai Hospital, Division <strong>of</strong> ReproductiveSciences, <strong>Department</strong> <strong>of</strong> Obstetrics and Gynaecology, Mount Sinai Hospitaland University Health Network, University <strong>of</strong> Toronto, Toronto, Canada4 <strong>Department</strong> <strong>of</strong> Obstetrics and Gynaecology, Mount Sinai Hospital andUniversity Health Network, University <strong>of</strong> Toronto, Toronto, CanadaBackground: If IVF/ICSI compared to spontaneous conception appreciably influencesNT, then this must be taken into account to calculate reliable Downs prenatal screenrisks. Whether IVF/ICSI actually affects NT in the first trimester is currentlycontroversial.Aim: To compare week 11-13 NT <strong>of</strong> singleton IVF/ICSI and spontaneous pregnancieseliminating potential confounders by matching NTs by sonographer, gestational age(CRL) and date <strong>of</strong> measurement (DOM).Methods: METHODS: This is a retrospective matched case control study. 449 selfreportedIVF/ICSI singleton pregnancies screened (2006-09) for Downs using NT wereidentified and the delta NT and MoM NT related to the expected (median) NT <strong>of</strong>gestation matched (CRL) non- trisomic pregnancies were recorded. Non IVF/ICSIpregnancy delta/MoM NTs <strong>of</strong> NTs measured by the same sonographer were matched tothose <strong>of</strong> each IVF/ICSI pregnancy and ranked by proximity <strong>of</strong> their DOM (max ±90 day)and associated CRL (max ±5 mm) to those <strong>of</strong> the IVF/ICSI pregnancy. Ranked matchedNTs in order <strong>of</strong> rank were retained if not already matched to another IVF/ICSI pregnancyand if fewer than 4 matches. The final database contained 411 IVF/ICSI pregnancies(7 with only 3 matches) along with 1637 non-IVF/ICSI pregnancies. Delta and MoM NTwere separately compared between the two pregnancy groups by Students T Test.Results: The mean MoM NT (SD) <strong>of</strong> IVF/ICSI and spontaneous singleton pregnancieswas 1.04 (0.28) and 1.03 (0.35), respectively. Corresponding data for the delta NT was0.07 (0.43) and 0.05 (0.52). In neither case was the difference statistically (or clinically)significant.Conclusion: Week 11-13+6 NT does not differ significantly between IVF/ICSI andspontaneous pregnancies thereby obviating the need to apply special IVF/ICSI correctionfactors to the expected NT in order to calculate reliable Downs prenatal screen risk. Thisstudy is distinguished by its careful matching <strong>of</strong> potential confounders and inclusion <strong>of</strong> alarge number <strong>of</strong> pregnancies.71 <strong>of</strong> 71