Department of Medical Imaging - University of Toronto

University of Toronto Department of Medical Imaging Research Day 2007DEPARTMENT OF MEDICAL IMAGINGANNUAL RESEARCH DAY 2007Date: Thursday, April 26, 2007Location: Ben Sadowski Auditorium, Mount Sinai Hospital (18th floor)Starting Time: 10:00 AM with welcome by Walter KucharczykChest, Breast, and Paediatric ImagingSession Chair: Marshall Sussman10:10 AM Kebby King Radiographic Response of Pulmonary TB to Anti-tuberculosis Treatment: A RetrospectiveStudy10:18 AM George Dong Correlation of the Quantitative and the Qualitative Emphysema Assessment UsingSoftware YACTA10:26 AM Demetris Patsios Low-Dose Computed Tomography as a Screening Tool Post Prior Asbestos Exposure forEarly Lung Cancer and Mesothelioma10:34 AM Anna Walsham Assessment of 2nd Generation Computer-aided Detection Software for the Detection ofPulmonary Emboli at CT Angiography10:42 AM Chris Mongiardi The Utility of a Computer Aided Detection Tool as a Second Reader for Junior Residentsin the Diagnosis of Pulmonary Embolism10:50 AM Hamid Bayanati Low Dose Chest CT Scan in Current and Former Smokers: Screening for Lung Cancer10:58 AM Hany Kashani Computer Assisted Pulmonary Nodule Volumetry: Reproducibility of VolumeMeasurement of Stable Small Pulmonary Nodules on Subsequent CT Scans11:06 AM Alexander McGregor Computer-aided Detection of Pulmonary Nodules: Effect of Reconstruction Algorithm onReproducibility of Pulmonary Nodules Volume Measurement11:14 AM Yuen-Li Ng CT-Guided Percutaneous Fine Needle Aspiration Biopsy of Pulmonary NodulesMeasuring 10mm or Less11:22 AM Igor Sitartchouk Characterization of Solitary Pulmonary Nodules: Comparison of Dynamic ContrastenhancedCT and FDG-PET Imaging11:30 AM Tal Arazi-Kleinman Can Breast MRI Computer Aided Detection (CAD) Improve Radiologist Accuracy forScreening MRI Detected Lesions Recommended for Biopsy in a High-risk Population?11:38 AM Anabel Scaranelo Clinical Performance of Computed-Assisted Detection (CAD) in Full-Field DigitalMammography Detecting Malignant Microcalcifications11:46 AM Bilal Ahmed Cumulative Doses in Children from Radiation Associated with Diagnostic Procedures11:54 AM Diana Glennie Measuring Pediatric Patient Doses in Interventional Radiology Using MOSFETs12:02 PM Minoo Bozorgzadeh Assessment of CT-PA – Indirect Venography for Technical Quality and Venous DVTDetection Compared to Leg Doppler Ultrasound12:12 PM Lunch (1 hour)NeuroimagingSession Chair: David Mikulis1:15 PM David Mikulis Assessment of Cerebrovascular Reserve with BOLD CVR MRI: A Promising NewMethod for Distinguishing Embolic from Hemodynamic Symptoms in Patients withCarotid Steno-occlusive Disease1:23 PM Danny Mandell Vascular Steal in the White Matter of Normal Brain1:31 PM Anisa Mnyusiwalla Radiation Dose from Multi-Detector CT Imaging for Acute Stroke1:39 PM Sandeep Bhuta Fast Quantitative Analysis of Hippocampal Atrophy in Patients with Mesial TemporalSclerosis Using 3Tesla MR Imaging1:47 PM Aditya Bharatha Intracranial Arterial Fenestrations: Frequency at CTA and Association with OtherVascular Lesions1:55 PM Ryan Wada Apparent Diffusion Coefficients Can Predict Primary Parotid Tumor Types1 of 54

University of Toronto Department of Medical Imaging Research Day 20072:03 PM Robert Yeung Comparison of CTA to DSA in Determining the Etiology of Spontaneous,Nonsubarachnoid Intracranial Hemorrhage2:11 PM Jeremy White Reliability of Automated Vessel Analysis Software in the Measurement of Carotid ArteryStenosis on CT Angiography2:19 PM Richard Farb The Venous Distension Sign: A Diagnostic Sign of Intracranial Hypotension at MR of theBrain2:27 PM Robert Kurtz Gadolinium Enhancement in Hyperacute Ischemic Stroke and its Predictive Value forHemorrhagic Transformation2:35 PM Richard Bitar Correlation Between Carotid Intraplaque Hemorrhage and Ipsilateral Perioperative AcuteIschemic Events in Patients Undergoing Carotid Endarterectomy for High-grade CarotidArtery Stenosis2:43 PM Gahl Greenberg Non-invasive MRI Assessment of Lateral Geniculate Nucleus in Glaucoma Patients2:51 PM Peter Howard Measurement of Carotid Stenosis on CTA: Reliability Depends on Post ProcessingTechnique3:01 PM Break (10 min)Vascular and InterventionalSession Chair: Dheeraj Rajan3:13 PM Michael Crawford Reliability of Inferior Vena Cava Measurements During Cavography3:21 PM Igor Kogan Post-procedural Complications of Outpatient Primary Stenting for Renal Artery Stenosis3:29 PM Dheeraj Rajan Patency and Complications of Tunneled Femoral Hemodialysis Catheters3:37 PM David Gianfelice MR Guided Focused Ultrasound Treatment of Bone Metastases3:45 PM Marshall Sussman Remote-Control CT-Fluoro-Guided Needle Alignment for Biopsy3:53 PM Eldon Lehmann Treatment Effectiveness and Patient Survival Following Radiofrequency Ablation ofUnresectable Hepatocellular Carcinoma in 411 Consecutive Patients: Analysis of a 7-YearExperience4:01 PM Sergey Litvin Imaging Evolution of Ablation Zones on CT Scanning After Radiofrequency Ablation ofLiver Tumors4:09 PM Ryan Margau Comparison of Ultrasound Versus Magnetic Resonance Imaging Prior to Uterine ArteryEmbolization in Symptomatic Patients with Presumed Uterine FibroidsAbdominal, GU, GI, and MSKSession Char: Martin O'Malley4:19 PM Tae Kyoung Kim Small Nodules (10-20 mm) in Liver Cirrhosis: Characterization with Contrast-enhancedUltrasound4:27 PM Yang-Yi Ong Recurrent Hepatocellular Carcinoma: Are Enhancement Features on Contrast-enhancedUltrasound Suggestive of Classic HCC or Metastases?4:35 PM Alexandre Menard Microcystic Adenomas of the Pancreas: Long-term Follow-up Measurement of Growth Rate4:43 PM Matthew McInnes Fetal Dural Sinus Malformations—Underrecognized and Underpublished?4:51 PM Philippe Sarliève Comparison of RECIST (Response Evaluation Criteria in Solid Tumor) Criteria and TumorAttenuation in Response to Sunitinib Therapy in Patients with Metastatic Renal CellCarcinoma (RCC)4:59 PM Martin O'Malley Testicular Cancer Surveillance: Standard Versus Low Dose CT5:07 PM Chris Dyck Accuracy of Ultrasound in the Diagnosis of Adnexal Torsion5:15 PM Hemi Dua Alternate Diagnoses in Pre-Embolization Imaging for Fibroids: The Importance of MRImaging5:23 PM Jennifer Stimec The Radiographic Quantification of Scapular Winging Following Malunion of DisplacedClavicle Shaft Fractures5:35 PM Walter Kucharczyk Closing Comments2 of 54

University of Toronto Department of Medical Imaging Research Day 2007Chest, Breast, andPaediatric Imaging3 of 54

University of Toronto Department of Medical Imaging Research Day 2007Radiographic Response of Pulmonary TB to Anti-tuberculosis Treatment:A Retrospective StudyKebby King, William Weiser, Jae YangPurpose: Multiple factors are considered in assessing patient response to Tuberculosis treatmentincluding radio-pathological and clinical assessment. The C-Xray reflects the treatment courseof the patient and can be used as a marker of the clinical response to treatment. An improving 6month C-Xray was evaluated as a marker of an uncomplicated treatment course.Method and Material: The response of pulmonary TB to treatment was retrospectivelyreviewed in 49 patients from June 2002 to July 12 2004 using the tuberculosis database at St.Michael’s Hospital. All pts were diagnosed bacteriologically or pathologically. Negative factorsoccurring during treatment including drug resistance, drug intolerance, positive sputum after 6months and disseminated disease were documented. The initial, 6 month follow up chest x-rayand the one year follow up chest x-ray were reviewed by a chest radiologist. Pleural,parenchymal and mediastinal disease were evaluated for improvement, no change or worsening.Results: Of the 49 patients, improvement was observed in 24 (49%), no change in 12 (24%),normal in 5 (10%) and worsening in 8 (16%) when comparing the initial with the 6 month followup chest x-ray. Of the 24 that showed improvement at 6 month follow up, 9 (37.5%) hadcomplications. Of the 20 that showed no improvement at 6 months 12 (60%) had complications.This was not significant (p= 0.2253). There was a trend for those who showed improvement at 1yr to have a higher proportion of complications 72.7% [8 of 11] compared with those whoimproved at 6 month 37.5% [15 of 24] p=0.075.Conclusion: The non-improving 6 month follow up chest x-ray cannot be used as a marker of acomplicated course alone. The study was limited by low power. There was a trend for those thatshowed late improvement to have more complications than those that showed earlyimprovement.4 of 54

University of Toronto Department of Medical Imaging Research Day 2007Correlation of the Quantitative and the Qualitative Emphysema AssessmentUsing Software YACTAGeorge Dong, Igor Sitartchouk, Hamid Bayanati, Hany Kashani,Claus P Heussel, Heidi RobertsPurpose: The purpose of this study was to compare a qualitative assessment of parenchymalemphysema by a chest radiologist with an automated, quantitative assessment using a home-builtsoftware tool (YACTA) in low-dose computed tomography scans of the chest.Material & methods: We retrospectively analyzed 141CT images from the lung cancerscreening study (I-ELCAP) or the asbestos screening study. All CT scans have been performedon different multidetector scanners (Light-speed QXi, Light-speed plus, Asteion and Aquillion64) in low-dose technique (120kV, 50~60mA), and reconstructed with thin slices (1.25 mm).The qualitative assessment has been performed before and describes the emphysema as none,mild, moderate, or severe.The in-house software used for the quantitative analysis is from the Department of Radiology inMainz, Germany (YACTA version 0.9). From the soft tissue reconstructed images of the CTscans, this software provides quantification of emphysema in terms of the parameters lungvolume, emphysema volume, emphysema index, mean low density (MLD) and its 15 thpercentile, as well as an overall grading of the emphysema (none, mild, moderate and severe).Results: According to the qualitative radiologist assessment, 79 individuals had no emphysema,43 had mild, 16 moderate and 3 severe emphysema. YACTA graded no emphysema in 72 cases,mild emphysema in 24 cases, moderate in 21 and severe in 24 cases.Comparing two qualitative assessments in all cases and in emphysema cases, the radiologist’sand YACTA grading show moderate correlation (r=0.46, p

University of Toronto Department of Medical Imaging Research Day 2007Low-Dose Computed Tomography as a Screening Tool Post Prior Asbestos ExposureFor Early Lung Cancer and MesotheliomaDemetris Patsios, Hamid Bayanati, George Dong, Narinder Paul,Michael Johnston, Heidi RobertsUniversity Health Network, Toronto, ON, CanadaAim: To screen asbestos workers for lung cancer and mesothelioma using low-dose computedtomography (LDCT).Methods: Enroll subjects with asbestos exposure of at least 20 years and/or documented pleuralplaques. LDCT is performed (40-60 mA, 120 kV, 1.25mm). We record: nodules, pleural plaques(extent, location, shape, thickness and calcification). Nodules are followed as per I-ELCAPprotocols; lobulated or asymmetric plaques, or plaques associated with pleural fluid are followedin 3–6 months. Interstitial lung patterns are noted: inter/intralobular septal thickening,groundglass opacities, honeycombing, architectural distortion, subpleural curvilinear lines, parenchymalbands, round atelectasis. In each lobe, each pattern is scored as 0(absence), 1(1 cm from thepleura), 2(within 2 cm from the pleura) and 3(>2 cm from the pleura).Results: 300 subjects screened so far, average age 62. 166(55.3%) are former, 72(24.0%)current and 62(20.7%) never smokers. Four lung cancers and one advanced mesothelioma weredetected (1.7%). 77% had pleural plaques: calcified (>80%), flat (>84%), and symmetric(>90%), involving the costal (>97%) and diaphragmatic (>88%) pleura. “Abnormal” plaqueshave a lobulated, asymmetric appearance with right-sided dominance, are associated with pleuraleffusions and are currently under surveillance. Qualitative scoring of non specific interstitialchanges is possible on LDCT:35% demonstrated features of parenchymal lung disease withscores ranging from 1-25/125.Conclusion: Screening prior asbestos workers can result in the early detection of lung cancer.For the detection of early mesothelioma we defined the appearance of “normal” vs. “abnormal”pleural plaques. The description of diffuse interstitial findings is an additional benefit of thisscreening program.6 of 54

University of Toronto Department of Medical Imaging Research Day 2007Assessment of 2nd Generation Computer-aided Detection Softwarefor the Detection of Pulmonary Emboli at CT AngiographyAnna WalshamPurpose of Study: To evaluate a second generation computer-aided detection (CAD) tool forthe detection of intravascular filling defects in pulmonary computed tomography angiography(CTA), and to assess its benefit for readers of different levels of experience.Materials, Methods and Procedures: 100 consecutive CTA exams performed to diagnose orexclude pulmonary embolism (PE) were retrospectively evaluated by a staff chest radiologist forthe presence and location of intravascular filling defects, serving as the reference standard.Subsequently, exams were analyzed using commercially available 2nd generation CAD software(ImageChecker CT, version 2.1 R2 Technology Inc., Sunnyvale, CA). The staff radiologistassessed all CAD marks and classified them as true positive (TP): CAD mark representing afilling defect; false positive (FP): CAD mark that was not a filling defect; false negative (FN):filling defect not marked by CAD. On a case-basis, a true negative (TN) was defined as anegative exam without CAD marks.Results: 21 of the 100 exams were judged to be positive for PE by the staff radiologist. In 18 ofthese cases, CAD correctly marked filling defects (18 TP, 3 FN exams). Of the 79 exams judgednegative for PE, 16 had no CAD marks (TN) and 63 had at least one CAD mark (FP). On a casebasis,CAD sensitivity and negative predictive value were 86% and 84% respectively (18/21 and16/19 respectively), specificity 20% and positive predictive value 22%. In the 21 PE positivecases, 93 individual PE were identified by the staff radiologist, of which 64 were correctlymarked by CAD (sensitivity 69%). Analysing individual marks, CAD generated a total of 254 FPmarks (average 2.5/case) with a PPV of 20%. Many FP CAD marks (>40%) were in perihilarlocations and easily dismissible.Conclusions: Though the PPV and specificity are limited by the number of FP marks, this 2ndgeneration CAD software is improved in sensitivity, and in the number and position of FP marks.However, further improvements in sensitivity and negative predictive value are desirable.7 of 54

University of Toronto Department of Medical Imaging Research Day 2007The Utility of a Computer-Aided Detection Tool as a Second Reader for Junior Residentsin the Diagnosis of Pulmonary EmbolismChris Mongiardi, Anna Walsham, Errol Colak, Hany Kashani, Demetris Patsios, Heidi RobertsPurpose: The purpose of this study was to assess whether or not a computer-aided detection(CAD) system would help inexperienced readers in the detection of pulmonary arterial fillingdefects.Materials and Methods: 100 unselected CTPAs performed to rule out pulmonary embolismwere retrospectively evaluated by a Junior Resident with one year of Radiology “on call”experience. Scans were initially interpreted without CAD software. Immediately after the initialread, they were reread with a commercially available CAD system (ImageChecker CT V2.1, R2Technology Inc., Sunnyvale, CA). The system is designed to mark potential filling defects inpulmonary arteries for further review and characterization. Cases were collected withoutknowledge of the clinical outcome or any other underlying diseases. The interpretation by achest radiologist served as the gold standard for case sensitivity. Studies were classified aspositive or negative for pulmonary thromboembolism and no indeterminate or equivocalcategory was employed. The junior residents confidence in interpretation was subjectivelyassessed pre and post CAD. A change in confidence or ultimate decision was documented. Inaddition assessment of technical quality of each scan, the time required for reading, and thenumber of correctly diagnosed cases, each without and with CAD were logged.Results: Of the 100 CT pulmonary angiograms reviewed, 21 were positive for acute pulmonaryembolism by the reference standard. The Junior Resident interpreted the same 21 cases positivebut also over called 9 additional cases (majority of low confidence), interpreting a total of 30cases positive for pulmonary embolism. The mean time for reading each study was 3:40 (9:58-1:23) minutes without CAD and 4:17 (12:03-1:23) minutes with CAD. Without CAD, theconfidence numbers were 27 (low), 32 (moderate) and 41 (high). With CAD, the confidencenumbers were 19 (low), 37 (moderate) and 44 (high). Overall CAD influenced (increased) thereaders’ confidence in 11 cases. In 9 of these cases no PE was detected and CAD did not mark afilling defect (true negative marks). The residents overall decision was not influenced by CAD.Conclusion: Utilizing CAD software for the automated detection of pulmonary embolism by ajunior radiology resident resulted in a slight increase in average reading time and improvement inconfidence. CAD had no effect on accuracy of readings. This suggests that in certain clinicalsituations CAD software may play a role as a second read for inexperienced readers.8 of 54

University of Toronto Department of Medical Imaging Research Day 2007Low Dose Chest CT Scan in Current and Former Smokers: Screening for Lung CancerH. Bayanati, H. C. Roberts, D. Patsios, N. S. Paul, M. McGregor, G. Weisbrod, T. Chung,S. Boerner, A. Pereira, I. Sitartchouk, Zhi Dong, M. Tsao, F. A. ShepherdIntroduction: Since 2003, the Department of Medical Imaging at the University HealthNetwork in Toronto is part of the International Early Lung Cancer Action Program (I-ELCAP).We report the results on the first 2970 participants.Methods: We enrolled high-risk smokers (at least 10 pack-year), 50 years or older, between06/2003 and 12/2006 a low-dose helical CT (40mA-60mA, 120kV) was performed with 1.3mmcollimation. Nodules found at baseline were followed according to the I-ELCAP protocol: (1) Nonodule, solid nodule ≤4mm or non-solid nodules < 8 mm: annual repeat; (2) Solid nodules ≥5mm or non-solid nodules ≥8 mm: 3 months follow up, (3) Nodules ≥15 mm: antibiotics and 1month follow-up or an immediate CT-guided biopsy.Results: The first 2970 participants had average age of 61 (median 60) years old, 1349 male and1621 female. Average smoking history was 34 pack-years (median = 30), 2072 (69.8%) former,898 (30.2%) current smokers). 660 individuals (22..2%) had a positive baseline LDCT:587(19.8%) were followed after 3 months, 43 (1.4%) after one month, 13 (0.4%) received acontrast-enhanced CT and 17 (0.6%) immediate biopsy.Overal 55 invasive procedures were performed: 52 CT-guided biopsies, 1 ultrasound-guidedlymph node metastasis biopsy, 1 bronchoscopy and 1 surgery. The malignancy rate of thebiopsies was 78.2%. Overall, 43 malignancies were found; 2 plasmocytoma, 1 carcinoid and 40lung carcinomas (prevalence 1.35%, 1.67% in female and 0.96% in male). Histology revealed 37NSCLC (30 adenocarcinoma/BAC, 6 squamous and 1 large cell) of which 27 (73%) were stage Iand 3 small cell carcinoma of which one staged limited and had surgery.Conclusion: Our results confirm that LDCT identifies small, early-stage resectable lung cancersin high risk population, the cancer prevalence within female study participants is higher than inmale participants; most cancers found are adenocarcinomas.9 of 54

University of Toronto Department of Medical Imaging Research Day 2007Computer Assisted Pulmonary Nodule Volumetry: Reproducibility of VolumeMeasurement of Stable Small Pulmonary Nodules on Subsequent CT ScansH. Bayanati, I. Sitartchouk, H. Kashani, N. Paul, H. RobertsPurpose: To assess the variability of repeated lung nodule volume measurements usingcomputer assisted diagnostic (CAD) software on computed tomography (CT) in documentedstable pulmonary nodules.Methods: From the lung cancer screening population we selected 101 well-defined, solidnodules which had been stable on follow up, assessed with double-read. All nodules had beenscanned in low-dose technique (50mA – 60mA, 120 kV) and reconstructed with 1.3mm slicethickness. Average time interval between the scans was 16 months (range 3 to 33 months,median 16), and overall observation time was from June 2003 to April 2007. Soft tissue and lungreconstructions of baseline and follow-up images were analyzed by a commercially availableCAD (ImageChecker CT, version 2.1 R2 Technology Inc., Sunnyvale, CA) for nodule volumemeasurement. The percentage volume change (PVC) for each nodule was documented.Results: The 101 nodules were between 2 mm and 15 mm in diameter (average 5.6 mm, median5.0). 77 were parenchymal, 24 pleural-based; 11 were calcified. 22 nodules were in RUL, 9 inRML, 22 in RLL, 18 in LUL and 30 in LLL. 55 nodules had an apparent larger volume on followup, 46 nodules had a smaller volume. Mean PVC was 19.46% (SD = 19.18%, SEM = 1.99%) forsoft tissue and 17.89% (SD = 15.37%, SEM = 1.59%) for lung reconstruction. The lower andupper quartiles of PVC were 5.06% and 29.59% in soft tissue reconstruction and 5.91% and26.68% in lung reconstruction. Correlation between volumes on baseline and follow-up was high(0.98 for both soft tissue and lung reconstruction). There was no significant difference amongmean PVC in soft tissue and lung reconstruction, parenchymal and pleural–based nodules,nodules located in lower lobes and upper lobes as well as between all sizes and 4-15 mmnodules.Conclusion: CAD nodule volume measurements in stable nodules show a high variation onrepeated scanning; which is more obvious in soft tissue compared to lung reconstruction.Clinical relevance/application: Pulmonary volume measurements are less variable on lungreconstruction than on soft tissue reconstruction. Variation on repeated measurements howeverremains high warranting a cautious interpretation of apparent lung nodule volume changes onrepeated CT based measurements.10 of 54

University of Toronto Department of Medical Imaging Research Day 2007Computer-aided Detection of Pulmonary Nodules: Effect of Reconstruction Algorithm onReproducibility of Pulmonary Nodules Volume MeasurementA. McGregor, H. Bayanati, D. Patsios, I. Sitartchouk, A. Pereira, H. RobertsPurpose: To evaluate the effect of reconstruction algorithm on reproducibility of a computeraideddetection (CAD) software for pulmonary nodule detection.Materials, methods and procedures: Computed tomography (CT) scans of 47 patients ( 24men, 23 women; mean age, 64 years; age range, 29-80 years) with lung cancer or pulmonarymetastases were prospectively reconstructed both with lung and soft tissue algorithms at 1 mmslice thickness, resulting in 2 sets of images. These were analyzed using commercially availableCAD software (ImageChecker CT, version 2.1 R2 Technology Inc., Sunnyvale, CA). All CADmarks were reassessed by two chest radiologists to exclude false positives. Those nodulesdetected both on soft tissue and lung reconstruction were selected and the calculated volumemeasurements were documented. The Pearson correlation was applied to assess correlation, apaired t-test was used to test differences between the groups.Results: Overall, 144 lung nodules (130 parenchymal and 14 subpleural) were found by bothsoft tissue and lung reconstruction series. There were 3 calcified, 141 solid non-calcified, and nonon-solid nodules. None of the nodules were endobronchial. Nodule volumes averaged 464.01mm 3 (median, 162.5 range, 16- 5207 mm 3 ) in soft tissue reconstruction and averaged 407.81mm 3 (median 127.5, range, 17- 4462 mm 3 ) in lung reconstruction. Nodule volume measurementshighly correlated (r=0.979), but nodules volumes were statistically significantly different(p=0.001), with the soft tissue reconstruction overestimating the volume compared to the lungreconstruction.Conclusions: CAD performance on pulmonary nodule volume measurement is influenced bythe reconstruction algorithm. Using temporal comparison for growth assessment requiresmeasurements based on identical reconstruction algorithms.11 of 54

University of Toronto Department of Medical Imaging Research Day 2007CT-Guided Percutaneous Fine Needle Aspiration Biopsy of Pulmonary Nodules Measuring10mm or LessY-L Ng, D Patsios, H Roberts, A Walsham, NS Paul, TB Chung, S Herman, G WeisbrodAim: To determine the value of CT-guided FNAB of small pulmonary nodules that would notbe considered suitable for assessment with Positron Emission Tomography.Material and Methods: CT-guided FNAB of 55 nodules, measuring 10mm or less, wereperformed between January 2003 and February 2006. A coaxial technique was used, with anouter 19G Bard Truguide needle and inner 22G disposable Greene Biopsy needle. Adequacy ofspecimens was assessed on-site by a cytotechnologist. The sizes of nodules, distance frompleura, number of pleural punctures and aspirates, complications encountered, cytologicaldiagnosis and outcome were recorded.Results: The mean nodule diameter was 9.0 mm (range 5–10 mm). The average distance fromcostal pleura was 31 mm (range 0-88 mm). In 50 of the 55 FNABs, the pleura was crossed once.An average of 4 aspirates was performed per case. Twenty-five FNABs (45.5%) were adequatefor diagnosis (24 malignant and 1 tuberculosis). In 16 cases, where no definite diagnosis wasmade following FNAB, the outcome has not been affected. In 10 cases, samples wereinsufficient for diagnosis and were diagnosed as malignant subsequently. Eight cases wereexcluded in the final analysis as follow-up details were unavailable. The sensitivity formalignancy and overall accuracy were 67.7% and 78.8% respectively. Pneumothorax occurred in29 (52.7%) patients, with 5 (9.1%) requiring thoracostomy tubes.Conclusion: CT-guided FNAB is a useful tool in the diagnosis and management of smallpulmonary nodules, despite the lower diagnostic accuracy and higher complication rate thanthose of larger pulmonary lesions.12 of 54

University of Toronto Department of Medical Imaging Research Day 2007Characterization of Solitary Pulmonary Nodules:Comparison of Dynamic Contrast-enhanced CT and FDG-PET ImagingI Sitartchouk, H Bayanati, Y-L Ng, G Dong, H RobertsIntroductionDynamic contrast-enhanced computed tomography (DCE-CT) with subsequent kinetic analysiscan be used to assess the angiogenic activity of solitary pulmonary nodules (SPN).Positron emission tomography enhanced with 2-[fluorine-18] fluoro-2-deoxy-D-glucose (FDG-PET) reflects the metabolic activity of tumors.The purpose of this study is to compare the angiogenic and metabolic activities of SPN usingDCE-CT and FDG-PET imaging respectively.MethodsData from studies of pulmonary nodules at our institution were retrospectively reviewed. Thesestudies have been approved by ERB. Between February 2005 and October 2006, we identified 10patients with SPN who underwent both DCE-CT and FDG-PET examinations, from 0 to 28 daysapart, without any interval treatment. The patients comprised of 5 men and 5 women, with a meanage of 65.4 years (range 51 to 80 years).A low dose (140kV, 50mA) cine CT study, without table movement, was acquired during theadministration of 50 ml contrast agent (flow rate 3-5 ml/sec), for approximately 25 sec, with ~1sectemporal resolution. Imaging was started with a delay of 10 sec after contrast injection, assuringacquisition of a few non-enhanced baseline data. A slab of 2 cm thickness was covered; four sliceswith 5 mm thickness each were reconstructed. Of these four slices, the slice through the largestportion of the nodule was chosen for analysis. Data analysis was performed with the CT Perfusion 3software (Advantage Windows, General Electric Medical Systems, Milwaukee, WI), yielding mapsand ROI estimates of fractional blood volume, blood flow, mean transit time and microvascularpermeability.A standard PET-CT imaging technique was used. Using standard software installed on the PETsystem, the FDG uptake within the tumor was expressed as the standardized uptake value (SUV).SUV is used to quantify the metabolic activity. A SUV greater than 2.5 has defined the SPN asmalignant with a relatively high degree of sensitivity and specificity (96.8% and 77.8% respectively).The DCE-CT perfusion parameters were compared to the SUV. The correlation coefficientswere calculated using the Pearson correlation coefficient. The sizes, histology and pathologicalstages of the nodules were recorded.ResultsThe nodules had a mean (± SD) diameter of 21.3 ± 6.5 mm (range 9 to 33 mm). The SUV wasgreater than 2.5 in 7 nodules; two adenocarcinomas and the unknown nodule were metabolically nonactive.The mean ± SD of the fractional blood volume (BV) was 10.2 ± 4.4 ml/100g, blood flow (BF)122.1 ± 79.2ml/100g/min, mean transit time (MTT) 9.2 ± 6.2 s and microvascular permeability (PS)26.0±16.9 ml/100g/min.The results show no significant correlation between SUV and the perfusion parameters fromDCE-CT.ConclusionOur preliminary results indicate that there is no significant correlation between the angiogenicand metabolic activity of a SPN as assessed by DCE-CT and FDG-PET imaging. Both thesetechniques may reveal additive rather than redundant information for the characterization of SPN.Further comparative studies with nodules of different histology are required to confirm these findingsand to better understand tumor biology at the molecular level.13 of 54

University of Toronto Department of Medical Imaging Research Day 2007Can Breast MRI Computer Aided Detection (CAD) Improve Radiologist Accuracy forScreening MRI Detected Lesions Recommended for Biopsy in a High Risk Population?Tal Arazi-Kleinman, Petrina A. Causer, Roberta A. Jong, Department of Medical Imaging,Sunnybrook Health Sciences Centre, University of TorontoEllen Warner, Kimberley Hill, Division of Medical Oncology, Department of MedicineSunnybrook Health Sciences Centre, University of TorontoDonald B. Plewes, Imaging Research and the Department of Medical Biophysics, SunnybrookHealth Sciences Centre, University of TorontoPurpose: To retrospectively evaluate the effect of MRI CAD on the radiologists’ sensitivity andspecificity for breast MR screen detected lesions recommended for biopsy in a high riskpopulation.Material and Methods: Fifty six consecutive BI-RADS 3-5 lesions with histopathologiccorrelation (9 invasive cancers (IC), 13 ductal carcinoma in situ (DCIS) and 34 benign) detectedon high risk patient screening MRI were retrospectively evaluated with breast MR CAD (CAD-Gaea). CAD evaluation was performed by 2 radiologists specializing in breast imaging, blindedto histopathology in consensus. Lesion enhancement at thresholds of 50, 80 and 100% anddelayed enhancement were independently assessed with CAD. Lesions were rated as malignantor benign with respect to background parenchymal enhancement according to threshold anddelayed enhancement only and in combination. Histopathology was compared to enhancementpattern with the chi-squared test. Sensitivities and negative predictive values (NPV) weredetermined for final CAD assessments vs. pathology and for IC and DCIS independently. InitialMRI BI-RADS interpretation without CAD vs. CAD assessments were compared with pairedbinary diagnostic tests.Results: Discriminatory threshold levels for lesion enhancement were: 50% for all cancers,DCIS and all benign lesions; and 100% for all IC. No correlation existed between delayedenhancement pattern and lesion pathology. The combined use of threshold and enhancementpattern information for CAD assessment was best (73% sensitivity, 56% specificity and 76%NPV for all cancer). However sensitivities and NPV were better for IC only (100%/100%)compared to DCIS only (54%/76%). Overall, radiologists’ MRI interpretation was moresensitive than CAD (p=0.05), but less specific (p=0.001) for cancer detection in a high riskpopulation.Conclusion: Current breast MR CAD using lesion enhancement information only cannotimprove the radiologists’ accuracy of distinguishing all malignant from benign screen MRIdetected lesions, due to the poor sensitivity for DCIS detection.14 of 54

University of Toronto Department of Medical Imaging Research Day 2007Clinical Performance of Computed-Assisted Detection (CAD) in Full-Field DigitalMammography Detecting Malignant MicrocalcificationsAnabel ScaraneloPurpose: To evaluate the performance of computed-assisted detection (CAD) in full-field digitalmammography (FFDM) in detecting malignant microcalcifications.Methods and Materials: The retrospective review of breast biopsies database revealed 175FFDM with microcalcifications without associated mass that were referred for biopsy. Thepathology findings included 54 malignant and 19 high-risk lesions. CAD-FFDM was applied inCC and MLO views. Dense breast tissue was defined as BI-RADS category 3 and 4 densities.Results: 50 of 54 (93%) of malignant microcalcifications were marked correctly by the CAD-FFDM system on the CC view and 78% in the MLO view (42 of 54). Overall cancer detectionrate was 96% (52 of 54).Size-related detection rate was 100% (20 of 20) for lesions larger than 10 mm in the CC viewand 90% (18 of 20) in the MLO view. Size-related detection rate was 94% (32 of 34) for lesionsup to 10 mm in at least one view, 85% (29 of 34) in the CC view and 71% (24 of 34) in the MLOview.CAD-FFDM system detected all cancers (29 of 29) in dense breast in at least one view and 97 %(28 of 29) using MLO view or CC view. The sensitivy of nondense breast was 92% (23 of 25) inat least one view and dropped to 64% (16 of 25) in the MLO view and 84% (21 of 25) in the CCview. The increase in sensitivy in dense breasts was found to be significant (p=0.0272) in at leastone view, in the CC view (p=0.0008) and MLO view (p=0.0002).Conclusion: The sensitivity of CAD-FFDM system for the detection of malignantmicrocalcifications in dense breasts is higher than previously reported. The performance ofCAD-FFDM was better on the CC view.15 of 54

University of Toronto Department of Medical Imaging Research Day 2007Cumulative Doses in Children from Radiation Associated with Diagnostic ProceduresBilal A. Ahmed, Puneet Shroff, Amy Lee Chang, Karen Thomas, Christopher Gordon,Ronald Grant, Mark Greenberg, Bairbre L. ConnollyPurpose: To assess the radiation burden from diagnostic and follow-up imaging in a cohort of150 children diagnosed with cancer in 2001, and followed to 2006.Materials and Methods: Retrospective analysis was performed of radiation exposure [Xrays,CT scans, Nuclear Medicine (NM)] from imaging histories of children, 30 each with leukemia(LK), lymphoma (LY), brain tumours (CNS), neuroblastoma (NB) and assorted solid tumors(ST).Results: There were 89 boys, 61 girls, aged 1 month – 17.5 years. The radiation exposure fromimaging for each group included:LK: 1-50 Xrays (mean=9.3, median=7), 0-11 CTs (mean=7.7, median=0), 0-3NM (mean=0.5,median=0), median cumulative dose = 2mSv.LY: 0-42 Xrays (mean=11.9, median=10.5), 2-28CTs (mean= 8.3, median=7), 0-24NM(mean=5.5, median=3), median cumulative dose = 244mSv.CNS: 0-24Xrays (mean=5, median=4), 0-13CTs (mean=4.43, median=4), 0-2NM (mean=0.3,median=0), median cumulative dose = 10mSv.NB: 3-63Xrays (mean=17.1, median=13.5), 2-31CTs (mean 13.8, median=11.5), 0-39NM(mean=16.3, median=13.5), median cumulative dose = 126mSv.ST: 1-63Xrays (mean18.9, median=12.5), 1-38CTs (mean 13, median=13), 0-24NM (mean=5.5,median=2), median cumulative dose = 92mSv.The radiation burden varied between groups. The distribution is skewed towards the low end forexposures. Dose estimates, based on imaging parameters per study, are presented.Conclusion: Radiation burden from imaging for children diagnosed with cancer variesconsiderably based on diagnosis and on individual clinical course.16 of 54

University of Toronto Department of Medical Imaging Research Day 2007Measuring Pediatric Patient Doses in Interventional Radiology Using MOSFETsDiana L. Glennie, Bairbre L. ConnollyBackground: Fluoroscopy is an imaging modality used with increasing frequency in pediatricinterventional procedures. There are very few studies recording the radiation dose to the patientsof these procedures.Objective: To measure the radiation surface doses incurred during some common pediatricinterventional procedures.Materials and methods: Five (5) MOSFET dosimeters were placed on patients’ skin in the areaof interest (in and around the area to be irradiated). The skin doses were recorded and comparedwithin each procedure type.Results: Data was obtained for 143 patients: 30 PICC insertions, 34 CVL/PORT insertions, 30G/GJ tube insertions, 25 sclerotherapy procedures, and 24 cerebral angiograms. The averageHighest Recorded Dose (HRD) was 2.51 mGy for the PICC insertions, 2.19 mGy for theCVL/PORT insertions, 2.48 mGy for the G/GJ tube insertions, 39.23 mGy for the sclerotherapyprocedures and 149.86 and 101.61 mGy for the frontal and lateral portions of the cerebralangiograms respectively. The returned data for all 5 MOSFETs for all procedures except thesclerotherapies (since the MOSFET locations varied) were analyzed separately. The dosereceived during the procedures did not relate linearly with fluoroscopy time, patient weight ornumber of Digital Subtraction Angiography (DSA) frames (where applicable).Conclusion: The doses received by pediatric patients during regular interventional proceduresare not negligible although they are consistently below the deterministic effect threshold.Procedures requiring ionizing radiation should be recorded in patient records to ensure thatadditional, unnecessary procedures aren’t recommended.17 of 54

University of Toronto Department of Medical Imaging Research Day 2007Assessment of CT-PA – Indirect Venography for Technical Quality and Venous DVTDetection Compared to Leg Doppler UltrasoundMinoo Bozorgzadeh, Department of Medical Imaging, University of Toronto.Harry Shulman, Department of Medical Imaging, Sunnybrook Health Sciences CentreJacques S. Lee, Department of Emergency Medicine, Sunnybrook Health Sciences CentrePurpose: To compare the technical quality of computer tomography pulmonary angiogram indirectvenography (CT-IV) to doppler ultrasound (DUS). To assess the specificity and sensitivity of CT-PA indirectvenography in detecting DVT compared to DUSMaterials and Methods: We reviewed the images and reports for 114 consecutive inpatients and outpatientswith intermediate to high pre-test probability for PE (considering VTE-protocol) undergoing CT-IV and DUSas part of their work-up for pulmonary embolus (PE).Both tests were completed within 36 hours of each other. When there was disagreement in the interpretation ofDUS and CT-IV (both tests were adjudicated by the principal investigator and classified as positive, negativeor indeterminate according to pre-specified criteria. We used DUS as the accepted clinical “gold standard” forthe diagnosis of DVT in femoropopliteal veins with approximately 95% sensitivity and 90% specificity. Caseswith indeterminate DUS were excluded from analysis to permit calculation of sensitivity and specificity of CT-IV.Technical quality of DUS was rated as good or poor, as described by an experienced ultrasonographer.Technical quality of CT-IV was rated as good, fair or poor based on pre-specified criteria, comparing theattenuation of common femoral vein (CFV) with adjacent muscle and common femoral artery (CFA). Wecalculated the sensitivity and specificity of CT-IV by including indeterminate (I) scans first among definitelypositive (P) cases and then including them among definitely negative (N) scans.Good – defined as – the attenuation of CFV is greater than the adjacent muscle and equal to that of CFA.Fair – defined as – the attenuation of CFV is greater than or equal to the adjacent muscle but less than theCFA. Poor – defined as – the attenuation of the CFV is less than that of the adjacent muscle and CFA.Results: Technical quality: 16 patients were classified as “Poor” in CT-IV (14%) as compared to 3 in DUS(4.4%) (McNemar’s chi-squared = 6.6667,df =1, p-value ≤ 0.01). Only two patients rated Poor in CT-IV werealso rated Poor in DUS. DVT detection: Among 111 patients with interpretable DUS, CT-IV was classified aspositive (P) for 14, negative (N) for 89 and Indetermiate (I) in 8.We calculated the sensitivity and specificity of CT-IV by including indeterminate (I) scans first amongdefinitely positive (P) cases and then including them among definitely negative (N) scans.Classifying I cases on CT as N / I with Pearson’s chi-squared test: X2=60.26, p-value=

University of Toronto Department of Medical Imaging Research Day 2007Neuroimaging19 of 54

University of Toronto Department of Medical Imaging Research Day 2007Assessment of Cerebrovascular Reserve with BOLD CVR MRI:A Promising New Method for Distinguishing Embolic from Hemodynamic Symptomsin Patients with Carotid Steno-Occlusive DiseaseDavid J Mikulis, Santanu Chakraborty, Daniel M Mandell, Jay Han, Julien PoublancToronto Western Hospital, Toronto, ON, Canada;Joe FisherToronto General Hospital, Toronto, ON, CanadaFrank SilverToronto Western Hospital, Toronto, ON, CanadaObjective: We hypothesize that BOLD (blood oxygen level dependent) CVR (cerebrovascularreserve) MRI has the potential to identify significant hemodynamic impairment in patients withcarotid steno-occlusive disease assisting in the discrimination of embolic from hemodynamicsymptoms.Methods: 13 patients with carotid steno-occlusive disease were referred for assessment ofcerebrovascular reserve (CVR) using BOLD (blood oxygen level dependent) MRI duringmanipulation of end tidal carbon dioxide (CO2). These patients were divided into two groupsbased on the presence (4 of 13) or absence (9 of 13) of TMB (transient monocular blindness).MRI was performed using an EPI gradient echo sequence with long TE (30 msec) designed to besensitive to blood deoxyhemoglobin concentration and is the same sequence used for fMRIexperiments at our institution. A unique gas sequencer and rebreathing mask were employedpermitting near square wave changes in end tidal CO2 between 30 and 50 mmHg with transitionsoccurring within 4 breaths during a 12 minute BOLD MRI acquisition. Quantitative maps ofcerebrovascular reactivity were obtained by using r value correlations of the end-tidal CO2waveform with the BOLD MRI signal. BOLD CVR maps, angiograms, and MRI perfusion timeto minimum maps (gadolinium bolus method) were correlated with clinical presentation.Angiograms were graded as follows: grade 0 = normal, grade 1 = < 70 % stenosis, grade 2 =70-90, and grade 3 = stenosis 90% or occlusion. Clincial symptoms were graded as present orabsent. None of these patients had prior infarcts.Results: BOLD CVR maps showed the highest correlation with clinical presentation in thosepatients without TMB compared to angiography and perfusion maps with the following r values:BOLD CVR = 0.57 (p less than 0.05), angiography = 0.33 (p > 0.05), and perfusion = 0.20 (p >0.05). r values in patients with TMB were: BOLD CVR = 0.12 (p > 0.05), angiography = 0.54(p > 0.05), and perfusion (not done as only one patient underwent perfusion in this group).Conclusion: The findings indicate that quantitative BOLD CVR MRI is more sensitive tohemodynamic impairment associated with steno-occlusive disease than angiography or perfusionimaging. As expected, BOLD CVR MRI was poorly correlated in patients suspected of havingembolic rather than hemodynamic symptoms. BOLD CVR MRI is a promising new method forassessing hemodynamic impairment offering the potential for identifying patients who are morelikely to benefit from revascularization procedures such as carotid stenting.20 of 54

University of Toronto Department of Medical Imaging Research Day 2007Vascular Steal in the White Matter of Normal BrainDaniel M. Mandell, Julien Poublanc, Jay Han, Adrian P. Crawley, Jeff A. Stainsby,Joseph A. Fisher, David J. MikulisIntroduction: The brain maintains relatively constant cerebral blood flow (CBF) despite changes incerebral perfusion pressure (CPP). This is accomplished by autoregulation of cerebral arteriole tone.Arterial pCO 2 is a key mediator of this response. Normally, inhalation of carbon dioxide causescerebrovascular dilatation, reducing cerebrovascular resistance, thus increasing CBF. Patients with avariety of cerebrovascular pathologies can have regions decreased CBF in response to CO 2 inhalation.This paradoxical response represents a vascular steal phenomenon whereby more normal regions of brainelicit increased blood flow at the expense of flow to more abnormal regions. Unexpectedly, using BOLD(blood oxygen level dependent) MR, we have also observed a paradoxical response in the hemisphericwhite matter of normal subjects. We hypothesized that there is statistically significant paradoxicalreactivity in the white matter of normal subjects, and that such paradoxical reactivity has a similar spatialdistribution to the pattern of deep white matter infarction seen in patients with carotid artery occlusion.Methods: Eighteen healthy volunteers (10 male, 8 female, age 22 – 42 years) were imaged on a 1.5 TGE MR scanner. We used a 3D SPGR pulse sequence to acquire T1-weighted images for anatomicalregistration. We then acquired CBF information (BOLD MR) using a T2*-weighted SS GRE pulsesequence with spiral readout. During the MR acquisition, we alternated between high and low end-tidalpCO 2 states (50 and 30 mm Hg respectively, SD 1 mm Hg) using an automated gas sequencer and rebreathingcircuit. We obtained maps of cerebrovascular reactivity (defined as Δ BOLD MR signal / Δend-tidal pCO 2 ) by least squares fitting of the BOLD MR signal waveform to the end-tidal pCO 2waveform on a voxel-by-voxel basis. All maps were transformed onto a standardized coordinate system.We then generated a composite map, derived from all 18 examinations, displaying mean reactivity.Voxels with paradoxical reactivity and a 90% confidence interval that excluded the value zero weredeemed statistically significant.Results: The mean cerebrovascular reactivity map showed regions of paradoxical response in thecentrum semiovale bilaterally. The attached figure shows this negative reactivity (black) overlaid on thecorresponding mean T1-weighted anatomical image.Conclusion: In normal subjects, the cerebrovascular autoregulatory response maintains blood flow to themajority of the brain at the expense of flow to the deep white matter. The spatial distribution of this stealis similar to the rosary pattern of white matter ischemic injury seen in patients with acute carotidocclusion. It is possible that this steal phenomenon is causative. Further, this steal phenomenon provides apotential mechanism for deep white matter injury secondary to reduced systemic blood pressure orincreased arterial pCO 2 , even in patients without underlying cerebrovascular disease.21 of 54

University of Toronto Department of Medical Imaging Research Day 2007Radiation Dose from Multi-Detector CT Imaging for Acute StrokeA. Mnyusiwalla, R. I. Aviv, A. J. Fox, S. SymonsSunnybrook Health Sciences CentrePurpose: CT has gained importance in guiding acute stroke management, particularly since thedevelopment of rapid acquisition CTA, CT perfusion and CT permeability imaging. While thebenefits of CT imaging in acute stroke include its ready availability, short time of acquisition andsensitivity in detecting hemorrhage; drawbacks include an increased delivery of ionizingradiation to the patient. The aim of our study was to determine the dose of ionizing radiationdelivered during CT imaging for acute stroke.Materials and Methods: All CT examinations performed at our institution over a 6 monthperiod using our Acute Stroke Protocol were included. The protocol involves an unenhanced CThead, CTA from the arch to vertex, perfusion, permeability and enhanced CT head acquired witha 64 slice MDCT. Examinations where any element of the protocol was repeated or omitted dueto mistimed injection or patient motion were excluded. The dose-length products (DLP) for allcomponents of each examination were obtained from dose reports generated at the time ofacquisition, separating neck and head calculations. Effective doses for each examination werecalculated using the DLP and normalized values of effective dose per DLP appropriate for thebody regions imaged.Results: A total of 63 examinations were included. The mean DLP was 6649.0 +/- 580.5mGy·cm. The effective doses ranged from 11.8 mSv to 19.6 mSv with a mean effective dose of16.0 +/- 1.9 mSv. The mean effective dose for acquisition of the unenhanced head was 2.7 +/-0.2 mSv. The largest contribution to effective dose was the CTA acquisition with a meaneffective dose of 5.0 +/- 1.7 mSv. The mean effective dose for CTP/permeability acquisition was4.9 +/- 0.0 mSv.Conclusion: Our CT Acute Stroke Protocol delivered a mean effective dose of 16.0mSv, whichis almost six times the dose of an unenhanced CT head. Although the radiation doses for acutestroke imaging with CT are high, these results must be balanced with the benefits to the patientfrom the detailed anatomic and physiologic data obtained.22 of 54

University of Toronto Department of Medical Imaging Research Day 2007Fast Quantitative Analysis of Hippocampal Atrophy in Patients with Mesial TemporalSclerosis Using 3Tesla MR ImagingSandeep Bhuta, Sean Symons, Allan Fox, George Tomlinson, David MikulisDept. of Medical Imaging, Division of Neuroradiology,Toronto Western Hospital, Sunnybrook Health Sciences CentrePurpose: Visualization of detailed anatomical structure at 3T compared to 1.5T can be achievedas a result of improved spatial resolution enabled by increased signal to noise. We have observedgreater detail in coronal images of the hippocampus at 3T including a structure that we believerepresents the Schaeffer collateral. We have decided to apply this knowledge for developing ameasurement scale that can be used to quickly ascertain the presence of hippocampal atrophywith high specificity in patients with mesial temporal sclerosis.Materials and Methods: 25 cases with unilateral mesial temporal sclerosis diagnosed byhistory, imaging, and EEG findings were compared to 25 patients referred with the diagnosis ofacoustic neuroma or pituitary adenoma. All subjects underwent a 3T MRI (GE Signa ExciteSystem with 8 Channel head coil) epilepsy protocol with the key measurement sequenceconsisting of a coronal fast STIR (Parallel factor 2, TR 6500, TE 41, Echo Train Length 12, Slicethickness 3mm with 1 mm gap, FOV 22 X 22 cm, Matrix 51 2X 512) oriented perpendicular tothe axis of the hippocampus.The 3T images revealed a linear band of decreased signal in the hippocampus presumablyrepresenting the Schaeffer collateral. The distance between this band and the outer margins ofthe hippocampus were measured superiorly, laterally, and medially on an Agfa Impaxworkstation by three Neuroradiologists blinded to all patient information (figure 1). The data wasthen analyzed to determine if there was a statistically significant difference between normal andatrophic hippocampi. This included t-test and ROC analysis for each linear measurement andcombined measurements.Results: ROC analysis indicated that the lateral measurement had poor sensitivity and specificitycompared to the superior and inferior measurements. It was therefore discarded and analysiscontinued by combining the superior and inferior measurements (combined measurement). Theareas under the ROC curves for each of the readers using the combined measurement wereReader 1 = 0.7, Reader 2 = 0.82, and Reader 3 = 0.61. There was an experience effect as reader2, who was the most experienced, had the highest area under the ROC curve. If the combinedmeasurement threshold from this reader of 3.4 mm is chosen, then the sensitivity of themeasurement is 64%, and the specificity is 96% (p < 0.0001) indicating that hippocampi withmeasurements smaller than this threshold should be considered atrophic.23 of 54

University of Toronto Department of Medical Imaging Research Day 2007Fig. 1: Coronal view of the right hippocampus showing the distances measured. Arrows pointto presumed Schaeffer Collateral.Conclusion: A fast measurement method for assessing the presence of hippocampal atrophy isproposed that offers high specificity for assisting in the diagnosis of mesial temporal sclerosis.24 of 54

University of Toronto Department of Medical Imaging Research Day 2007Intracranial Arterial Fenestrations: Frequency at CTA and Associationwith Other Vascular LesionsAditya Bharatha (Resident)Allan FoxRichard AvivSean Symons (Supervisor)Abstract:Fenestrations (segmental duplications) of the intracranial arteries are rare anomalies, felt to resultfrom incomplete fusion of primitive embryologic vessels. They have been associated withaneurysms and other vascular lesions. The rate of fenestrations based on published angiographicseries has been much lower than that at cadaveric dissection. The purpose of this study is todetermine the frequency of fenestrations and associated vascular lesions at CTA. 504 sequentialCTA studies from 2005 to 2006 were retrospectively reviewed for the presence of fenestration,aneurysm and other vascular lesions. Fenestrations were present in 53 patients (11%). Theirfrequency was similar in patients referred for aneurysm and non-aneurysm indications, despite amuch higher frequency of aneurysms in the former group. Associated vascular lesions wererelatively uncommon. Aneurysms were present at the fenestration in 3 patients, and remote fromthe fenestration in 7. One fenestration-aneurysm patient also had an AVM remote from thefenestration. The frequency of fenestrations in this study was higher than in previouslypublished radiologic studies, suggesting that fenestrations are relatively common, and may bemore frequently visualized using cross-sectional imaging. Association with aneurysm and othervascular lesions was relatively uncommon.25 of 54

University of Toronto Department of Medical Imaging Research Day 2007Apparent Diffusion Coefficients Can Predict Primary Parotid Tumor TypesR. Wada, E. Yu, D. Lazinski, E.E. KasselMount Sinai and Princess Margaret Hospitals, University Health Network,Toronto, Ontario, Canada.Purpose: To determine if calculated apparent diffusion coefficients (ADC) can distinguishbetween common primary benign and malignant parotid gland masses.Methods: ADC prediction of pathology for primary parotid tumors was studied in 51 patientswith solitary, unilateral parotid masses. MRI examinations were performed using conventionalsequences as well as single shot echo-planar diffusion weighted imaging at b factors of 0 and1000 s/mm 2 . The definitive diagnostic outcome was pathologic evaluation. Analysis wasperformed blinded to clinical information, pathology, prior reports, and standard MR sequences.Mean ADCs were calculated for each mass based on measurements in 3 separate defined tumorzones. Main analysis is a comparison of ADC values of the masses with the eventualpathological outcome.Results: Two patients were excluded from the study for lack of definitive pathology. Sinceonly one oncocytoma and one basal cell adenoma was uncovered in this series, these patientswere not included in the study. Therefore, a final cohort of 47 patients was evaluated. Based onpathologic analysis, masses were grouped into 3 categories: pleomorphic adenomas, Warthintumors and primary parotid malignancies. Mean ADC value for pleomorphic adenomas (1.81 x10 -3 mm 2 /s +/- 0.41 x 10 -3 mm 2 /s) was found to be significantly greater than for eithermalignancies (1.29 x 10 -3 mm 2 /s +/- 0.26 x 10 -3 mm 2 /s, p=0.0005) or for Warthin tumors (0.94 x10 -3 mm 2 /s +/- 0.25 x 10 -3 mm 2 /s, p

University of Toronto Department of Medical Imaging Research Day 2007Comparison of CTA to DSA in Determining the Etiology of Spontaneous,Nonsubarachnoid Intracranial HemorrhageRobert Yeung, Tabassum Ahmad, Lynne Noel de Tilly, Allan J. Fox,Richard R. Aviv, Sean P. SymonsDivision of Neuroradiology, Department of Medical Imaging, Sunnybrook Health SciencesCentre and St. Michaels Hospital, University of Toronto, Toronto, Ontario, CanadaPurpose: To compare the efficacy of computed tomography angiography (CTA) to that ofdigital subtraction angiography (DSA) at detecting the cause of spontaneous, non-subarachnoidintracranial hemorrhage.Methods: 44 patients were included in the study. All had CTA and DSA performed prior tosurgical intervention. All cases of intracranial hemorrhage were spontaneous without recenttrauma and were not primarily subarachnoid. Three reviewers independently analyzed the CTAsin a blinded protocol and classified the etiology into one of the following: 1) AVM, 2) AVF, 3)cavernous malformation, 4) tumor, 5) aneurysm, 6) DVA, or 7) negative/unknown. Results werecompared with the reference standard DSA.Results: The sensitivity of CTA for detecting the cause of hemorrhage for the three reviewerswas 0.91, 0.95 and 0.91. The specificity of CTA for the three reviewers was 0.91, 0.95 and 0.91.Kappa value for interobserver agreement ranged from 0.82-0.91. One of the 3 dAVFs wasmissed by all three reviewers.Conclusion: CTA is nearly as effective as DSA at determining the cause of spontaneous, nonsubarachnoidintracranial hemorrhage.27 of 54

University of Toronto Department of Medical Imaging Research Day 2007Reliability of Automated Vessel Analysis Software in the Measurement ofCarotid Artery Stenosis on CT AngiographyJ.H. White, E.S. Bartlett, R.I. Aviv, A.J. Fox, S.P. SymonsPurpose: To compare the reliability of automated vessel analysis software to manualmeasurement in the determination of carotid artery stenosis on CT angiography.Methods: Two observers separately analyzed 133 carotid artery CT angiograms using anautomated vessel analysis program according to a blinded protocol. The software measured thenarrowest stenosis in millimeters (mm), the distal internal carotid (ICA) in mm, and calculatedpercent stenosis based on NASCET criteria. Two separate observers manually measured thenarrowest stenosis in mm, the distal ICA in mm, and calculated percent stenosis based onNASCET criteria. Correlation coefficients were calculated for each group comparing narroweststenosis, distal ICA, and derived percent stenosis measurements.Results: The automated vessel analysis software provided excellent intraobserver andinterobserver correlation for minimum stenosis in mm, distal ICA in mm, and NACSET percentstenosis (Kappa 0.89, 0.90, and 0.85 respectively). The automated vessel analysis softwareprovided excellent interobserver correlation for the same parameters (Kappa 0.85, 0.83, and 0.90respectively). The interobserver correlation for manual measurement was good (Kappa 0.75,0.79, and 0.76 respectively). There was a statistically significant difference in the interobserverreliability between the automated vessel analysis software observers and the manualmeasurement observers (p < 0.05).Conclusion: Automated vessel analysis software is a highly reliable method of quantifyingcarotid artery stenosis. In this study, automated vessel analysis software determination of carotidstenosis was shown to be more reliable than manual measurement.28 of 54

University of Toronto Department of Medical Imaging Research Day 2007The Venous Distension Sign: A Diagnostic Sign of Intracranial Hypotensionat MR of the BrainRichard I. Farb MD 1 , Reza Forghani MD 2 , Seon Kyu Lee MD 1 , David J. Mikulis MD 1 ,Ronit Agid MD 11Department of Medical Imaging, Division of Neuroradiology, Toronto Western Hospital,University of Toronto, 399 Bathurst Street, Toronto, ON2Department of Medical Imaging McGill University, Montreal, QCBackground: Patients with intracranial hypotension (IH) demonstrate intracranial venousenlargement with a characteristic change in contour of the transverse sinus seen on routine T1weighted sagittal imaging. In IH the inferior margin of the mid portion of the dominanttransverse sinus acquires a distended convex appearance, we have termed this the venousdistension sign (VDS). This is distinct from the normal appearance of this segment whichusually has a slightly concave or straight lower margin. This sign is introduced and itsperformance as a test for the presence of this disease is evaluated.Methods: The transverse sinuses on T1 weighted sagittal imaging of 15 intracranial hypotensionpatients (IH) and15 control patients (CP) were independently assessed in a blinded fashion bythree readers for the presence of a VDS. A present or absent VDS was determined for eachpatient by each reader and a consensus result for each patient was determined by unanimity ormajority rule.Results: Using the VDS the readers correctly identified 93% (14 of 15) of the IH patients andsimilarly 93% ( 14 of 15) of the control patients. There was a high rate of agreement among thereaders for the interpretation of the VDS (multi-rater kappa =0.82). The overall sensitivity of theVDS for the diagnosis of intracranial hypotension was 94%. Specificity was also 94%.Conclusion: The “venous Distension Sign” is an accurate sign for determining the presence orabsence of intracranial hypotension.29 of 54

University of Toronto Department of Medical Imaging Research Day 2007Gadolinium Enhancement in Hyperacute Ischemic Stroke and its Predictive Value forHemorrhagic TransformationRobert KurtzBackground and Purpose: Enhancement on post-Gadolinium T1 weighted MR images in thesetting of hyperacute stroke (

University of Toronto Department of Medical Imaging Research Day 2007Correlation Between Carotid Intraplaque Hemorrhage and Ipsilateral Perioperative AcuteIschemic Events in Patients Undergoing Carotid Endarterectomy for High-grade CarotidArtery StenosisRichard Bitar, Alan Moody, Sean Symons, Richard Aviv, Susan Crisp,Alexander Kiss, General Leung, Robert MaggisanoPurpose: Carotid endarterectomy (CEA) is a proven method to decrease the incidence of strokesin patients with symptomatic/asymptomatic carotid artery stenosis (CAS). However,neurological deficits can occur perioperatively, and embolism accounts for >60% of allprocedure-related strokes. Intraplaque hemorrhage (IPH) is one of the markers that defineplaques as complicated, and is thought to promote plaque destabilization. By exploiting the T1shortening effects of methemoglobin, Magnetic Resonance Direct Thrombus Imaging (MRDTI)is a MR technique that directly visualizes carotid complicated plaques. The purpose of this studywas to evaluate if the presence of complicated plaque (as detected by MRDTI) correlated withperiprocedural acute DWI events.Methods: Twenty-seven patients (23 male, 4 female, mean age 72.9 ± 6 yrs) undergoing CEAfor high-grade symptomatic/asymptomatic CAS were imaged at 1.5T (GE) using MRDTI andDiffusion-Weighted Imaging (DWI). Both pre-operative and post-operative scans were obtained.Sequence parameters were: MRDTI (T1-weighted fat-suppressed spoiled gradient-echo,TR/TE/α/spatial resolution: 6.7ms/1.6ms/15 o /0.94mm 2 x1.0 mm), and DWI (DWI-EPI, TR/TE/Bvalue/spatial resolution: 9200ms/82.7ms/1000/2.1 x 1.4 mm). An 8-channel neurovascularphased-array coil was used (USA Instruments). The images were evaluated for presence ofcomplicated plaque and acute ipsilateral events on DWI/ADC maps. Statistical analysis wasperformed by using the Fisher’s exact test.Results: Mean-time-to-imaging for pre-operative and post-operative scans was 2.7 days and 1.1days, respectively. Eighteen of 27 (66.6%) carotids had IPH. Twenty-one periprocedural acuteDWI events were detected in 7 patients (all with IPH). This represented a mean number of 3lesions/IPH-positive patients and 0 lesions/IPH negative patients. Patients with complicatedplaques were more likely to have acute cerebral ischemic events compared to patients withoutcomplicated plaques (p=0.03)Conclusion: The presence of intraplaque hemorrhage correlates with perioperative acuteischemic events.Clinical significance/application: Detection of complicated plaques with MRDTI will behelpful in identifying those patients at risk for periprocedural acute ischemic events.31 of 54

University of Toronto Department of Medical Imaging Research Day 2007Non-invasive MRI Assessment of Lateral Geniculate Nucleus in Glaucoma PatientsGahl Greenberg, Neeru Gupta 1 , Yeni Yücel 2 , Lynne Noel de Tilly 3 , Bruce Gray 31 Glaucoma and Nerve Protection Unit, University of Toronto, St Michael’s Hospital Toronto,Ontario, Canada 2 Ophthalmic Pathology Laboratory, University of Toronto, St Michael’sHospital, Toronto, Ontario, Canada 3 Division of Neuroradiology, Department of MedicalImaging, St Michael’s Hospital, University of Toronto, Toronto, Ontario, CanadaPurpose: This study examines the hypothesis that glaucomatous damage would result inmeasurable atrophy of the LGN.Materials and Methods: This is a prospective masked study. Our population consisted of 20subjects, 11 of which (7F, 4M Mean age 60y (SD 9.97)) were glaucomatous patients diagnosedwith Moderate to advanced glaucoma and bilateral superior visual field defects. The remainderswere age-matched controls (6F, 3M Mean age 62y (SD 8.14)). Exclusion criterion was anyevidence of neurodegenerative disease. Scans were performed in two batches, a week apart.Brain MRI images (Philips Intera 1.5T) were obtained utilizing 2mm thick coronal protondensity sequences through the lateral geniculate nucleus (LGN). Additional sagittal T1 and axialT2 FLAIR images of the head were obtained for orientation as well as to rule out any evidence ofmajor abnormality along the visual pathways. Three neuroradiologists, masked to the clinicalinformation, made consensus measurements of the LGN based on agreed criteria. For each side,maximal height and distance from midline were recorded. The slice for measurement was chosenindependently for each nucleus, where nucleus gray matter was discernible and confidentlyseparated from other thalamic nuclei and medial geniculate nucleus.Results: LGN was readily detected on all images. The difference between the left LGN height inthe glaucoma group compared to the control group was significant (3.96 mm vs. 4.79 mm,p=0.0199). Although the height was also reduced in the right LGN, this did not reach statisticalsignificance. The combined total LGN height between the 2 groups was however statisticallydifferent (8.01 mm vs. 9.44 mm, p= 0.0038).Conclusion: This study shows there is a role for neuroimaging in the localization andmeasurement of LGN in the brain of patients with glaucoma. Our results do show a trendtowards measurable atrophic change of this major visual relay center, best portrayed as combinedheight. As this is a pioneer study, further research is required to provide more insight into centralnervous system changes in glaucoma.Acknowledgments: This work was partially supported by Canadian Glaucoma Research Council(Drs. N. Gupta and Y. H. Yücel)32 of 54

University of Toronto Department of Medical Imaging Research Day 2007Measurement of Carotid Stenosis on CTA:Reliability Depends on Post Processing TechniquePeter HowardPurpose: We have previously demonstrated the validity of axial source image quantification ofCT angiography (CTA) visualized carotid stenosis. There is concern that source images may notaccurately measure stenosis in patients with obliquely orientated stenosis and that measurementson axial oblique MPR images, MIP images or DUS are superior. We test the performance ofaxial source images against axial oblique MPRs, MIPs and DUS techniques for stenosisquantification.Methods: 120 consecutive patients with CTA and Doppler Ultrasound (DUS) detected carotiddisease were enrolled; carotids with occlusion, near occlusion, or stenosis 70% stenosis was assessed against aNASCET-style reference standard.Results: Intraobserver reliability for measurements of stenosis diameter is higher for axialimages (ICCs 0.86-0.92) than for MIPs (ICCs 0.70-0.86). Interobserver reliability is higher foraxial images (0.89-0.92) than for MIPs (ICCs 0.79-0.82). Intra and interobserver agreement onNASCET ratio is generally lower than interobserver agreement on proximal stenosis diameter.As a test for > 70% stenosis, proximal millimeter stenosis measurement on axial source imagesand axial oblique images was most accurate (0.90), and proximal measurement on MIP imageswas least accurate (0.76), while the accuracy of Doppler ultrasound was intermediate (0.83).Conclusion: With attention to technique, a single axial source image stenosis measurement ishighly reproducible and accurate in the estimation of carotid stenosis.33 of 54

University of Toronto Department of Medical Imaging Research Day 2007Vascular andInterventional Radiology34 of 54

University of Toronto Department of Medical Imaging Research Day 2007Reliability of Inferior Vena Cava Measurements During CavographyM Crawford, E HayeemsPurpose: Filter placement in the IVC for prevention of pulmonary embolism from lower limb /pelvic DVT is an established and safe treatment. Historically, IVC measurements prior to filterplacement are made using a metal ruler placed beneath the patient. Whilst complicationsincluding filter migration are rare, we hypothesise that measurements taken in this manner mayunderestimate the true size of the IVC and hence may inadvertently increase the risk of filtermigration. We therefore undertook this retrospective review to evaluate the accuracy of IVCmeasurements during cavography and review the incidence of filter migration.Materials and Methods: All patients who had undergone IVC Filter insertion at our institutionduring the period January 2000 to June 2006 were initially reviewed. 150 were found to haveundergone CT imaging of the abdomen within the preceding month and had cavography imageswith a metal ruler in place. Images were reviewed electronically. Transverse diametermeasurements of the IVC were obtained at 1 and 3 cm respectively below the right renal vein onboth cavography and CT. For the cavography measurements the ruler was used as the templateand the pixel value for 5cm used in each case for standardization to calculate approximate cavalmeasurement in centimetres.Results: The average transverse diameter of the IVC on cavography at 1cm and 3cms below theright renal vein are 1.6 and 1.5cm respectively. The corresponding measurements on CT are 2.3and 2.2 cm respectively. In almost all cases, cavogram measurements were lower than the CTmeasurements both at the 1cm site and at the 3cm site. This was confirmed by the results ofpaired t-tests which showed that the mean of the cavogram measurements was not equal to themean of the CT scan measurements at either site (1cm: t = -25.5, P< 0.0001; 3cm: t=-26.3, P

University of Toronto Department of Medical Imaging Research Day 2007Post-procedural Complications of Outpatient Primary Stenting forRenal Artery StenosisIgor Kogan, University of Toronto, Toronto, Ontario, Canada. Dheeraj K Rajan*, Kenneth WSniderman, John R Kachura, Eran Hayeems and Vernon Campbell. Et alPurpose: To determine the safety and complications of outpatient percutaneous renal arterystenting (PRAS) with recently introduced low-profile systems.Materials and Methods: From January 2001 to July 2006, 58 PRAS were performed. Of these,58 PRAS procedures were performed on 53 outpatients. Within the study cohort, there were 32males and 21 females with a mean age of 62.6 years. In total, 64 arteries were stented in 58PRAS sessions. Stenting was performed on those patients with demonstrated renal artery stenosisand poorly controlled hypertension and/or renal failure. The stent platform most commonly usedwas a low profile over the wire 0.018-inch delivery system. All procedures were performed onan outpatient basis with all patients stable at the time of discharge and accompanied by an adultfor the first 24 hours. Patients were observed for 6 hours following completion of the procedureprior to dischargeResults: The technical success rate of PRAS was 98.3%. Within the first 24 hours followingcompletion of the procedure 5 patients were admitted for 5 minor complications. In this cohort offive, there were four minor complications (two patients with puncture site hematomas requiringsupportive care, one patient with loss of a stent requiring deployment in the iliac artery, and onepatient with a renal artery dissection successfully treated with a covered stent), and there was onemajor complication of a large scrotal hematoma with sciatica, which was treated conservativelybut required overnight admission. One delayed minor complication was observed over 30 daysfollowing the procedure; the patient had a transient increase in serum creatinine level.Conclusions: With the introduction of low profile stent delivery platforms, outpatientpercutaneous renal artery stenting can be safely performed with limited major complications.Major complications necessitated admittance for a single patient (1.9%).36 of 54

University of Toronto Department of Medical Imaging Research Day 2007Patency and Complications of Tunneled Femoral Hemodialysis CathetersDheeraj K. Rajan, Jasdeep SalujaPurpose: To retrospectively review outcomes of tunneled femoral hemodialysis catheters andcomplications associated with their placement.Materials and Methods: A retrospective review of all tunneled hemodialysis catheters placedfrom October 1996 to June 2006 was conducted. Forty-eight patients of whom 21 males and 27females with a mean age of 59.8 years had tunneled femoral dialysis catheters placed. A total of126 catheters were placed of which 78 were replacements. In 77% of patients (37/48), theindication for catheter placement was lack of patent upper central veins. In 12.5% (6/48), thecatheter was placed to avoid using the left subclavian vein for future arm access or maturation ofaccess. In 10% of patients (5/48), catheters were placed for other reasons.Results: Technical success of all procedures was 100% with 92% clinical success. A total of 126procedures were performed. Primary patency including initial clinical failures for initial catheterplacement was 31% (95% CI, 5-57%), 25% (0-54%) and 15% (0-51%) at 3, 6 and 9 monthsrespectively. The infectious complication rate was 1.2 per 1000 catheter days requiring catheterremoval and abandonment of the access site in 4.7% of the procedures (6/126) and exchange forinfection in 7.1% (9/126). Catheter migration with cuff exposure occurred in 9.5% of cathetersplaced requiring catheter change. Catheter exchanges were performed for poor flows orthrombosis in 38.1% of procedures. With the exception of infection, no complications associatedwith catheter placement were observed.Conclusion: Tunneled femoral dialysis catheters are associated with poor short and mid-termpatency when compared to observed patency of tunneled upper central venous hemodialysiscatheters.37 of 54

University of Toronto Department of Medical Imaging Research Day 2007MR Guided Focused Ultrasound Treatment of Bone MetastasesD. Gianfelice, C. Gupta, D. Havill, W. KucharczykIntroduction: Image guided therapy has entered a new era with the advent of technologieswhich allow targeted destruction of focal lesions. Accurate focal tissue ablation is achieved bycombining image guided techniques to accurately situate energy conducting probes intopathological processes followed by delivery of different energy sources to achieve celldestruction. Cell necrosis can be achieved by conduction of thermal energy via the conductingprobes hence raising tissue temperature above 60c, as is the case in radiofrequency, laser andmicrowave ablation technology. Conversely, cell death can be achieved by the introduction ofextreme cold as in the case of cry therapy image guided techniques.MR Guided Focused Ultrasound Surgery: MR image guided focused ultrasound surgery(MRIgFUS) is a recent addition to the thermal therapy ablative technologies. This technique isunique in that no conducting probe is placed into the patient to achieve thermal ablation of focalpathologies. Thermonecrosis is produced by a phased array piezoelectric transducer, which canfocus high-energy ultrasound waves and specifically target focal lesions. MR imaging serves twopurposes in this process. MR acts as an accurate imaging method to delineate the pathologytargeted and more importantly provides instant feedback as to whether the targeted tissue has infact been ablated successfully. This feedback is achieved by utilizing specific MR imagingsequences, which allow accurate temperature readings to be obtained during the ablative process.This unique ability makes MRIgFUS the only true closed loop ablative technology availabletoday; each focused wave which is concentrated on a focal pathology is accompanied byinformation which accurately depicts whether cell death has been achieved.MRIgFUS Clinical Applications: Extensive animal and human studies have been completed todate utilizing MRIgFUS as an ablative mechanism. In human studies extensive work has beenpublished on treatment of focal breast lesions specifically fibroadenomas and non metastaticfocal breast carcinoma. Phase 3 studies for breast carcinomas have already commenced in Japanand MRIgFUS will soon be established as a possible alternative to standard surgical lumpectomyin certain population groups with breast carcinoma.MRIgFUS has been used extensively for the treatment and symptomatic relief in patients withuterine fibroids. Although follow up studies are limited to approximately three years thistechnology has already been established a non-invasive outpatient alternative to surgicalhysterectomy and uterine artery embolization.38 of 54

University of Toronto Department of Medical Imaging Research Day 2007MRIgFUS Present/Future Applications: MRIgFUS is now being evaluated for the palliativetreatment of painful bony metastases. Focused energy directed at the periosteum and alsoablating the tumor lesion has shown promise with significant pain reduction in this patientpopulation. Studies at UHN are the first North Americain experience and have shown greatpromise.To date 10 patients have been treated with significant reduction in pain associated with theirbone lesion in all patients.MRIgFUS will offer non-invasive ablative alternative for a variety of focal neoplastic processes.Recent literature suggests that with advanced imaging techniques such as MR spectroscopy ordynamic contrast MR sequences, focal neoplastic processes of the prostate gland can beaccurately localized and hence biopsied followed by a local ablative procedure. Via anendorectal probe MRIgFUS will offer an accurate non-invasive method to destroy the prostatictumour process with limited morbidity. This focal ablation will significantly reducecomplications such as loss of potency associated with surgical prostatectomy and whole glandablative techniques.Conclusion: MRIgFUS is a new and exciting ablative technology with numerous applications,which will be established, in the next few years. The advantages of this technique include closedloop immediate feedback as to the progress of the ablative procedure as well as the eliminationof the placement of an external device into the patient to deliver the energy source to the tumourprocess.39 of 54

University of Toronto Department of Medical Imaging Research Day 2007Remote Control CT-Fluoro-Guided Needle Alignment for BiopsyMarshall S. Sussman, Andre Pereira, Walter KucharczykDepartment of Medical Imaging, University of Toronto, UHNThe alignment of a biopsy needles under CT guidance often has to be adjusted multipletimes, before successful targeting is achieved. This results in extended procedure times, andadditional radiation dose. Our objective is to develop a system that will maintain the accuracy ofconventional biopsy, but at a reduced procedure time and x-ray dose. This will be accomplishedthrough the development of a remote-controlled CT biopsy device. Our initial work is focussedon optimizing the initial needle alignment stage of the biopsy procedure. Towards this end, aneedle holder device was built that is capable of positioning the biopsy needle by remote controlfrom the CT scanner control room under real-time CT fluoroscopy control. During the biopsyprocedure, this remote-control positioning device is positioned above the patient in the CTscanner. A series of CT fluoro images are acquired, in which the needle is rotated until it alignswith the target lesion. The needle is then advanced towards the lesion by the radiologist, as inconventional procedures. This approach has the potential of reducing dose and procedure timethrough two avenues: First, because the lesion and device manipulation are viewedsimultaneously, it is hypothesized that more rapid targeting will result. Second, since singleslicelow-dose CT fluoro rather than high-dose diagnostic CT images are used for targeting, it ishypothesized that overall x-ray dose will be further reduced. In this presentation, some initialwork performed on phantoms with this device will be presented.40 of 54

University of Toronto Department of Medical Imaging Research Day 2007Treatment Effectiveness and Patient Survival Following Radiofrequency Ablationof Unresectable Hepatocellular Carcinoma in 411 Consecutive Patients:Analysis of a 7-Year ExperienceEldon D. Lehmann 1,2 , John R. Kachura 1 , C. S. Ho 1,2 , J. Robert Beecroft 1 ,George A. Tomlinson 3 , Steven Gallinger 4 , et al.1. Division of Vascular and Interventional Radiology (VIR), Department of Medical Imaging;2. Division of Abdominal Imaging, Department of Medical Imaging; 3. Departments of Medicineand Public Health Sciences; and 4. Department of Surgery; Toronto General Hospital andMount Sinai Hospital, University of TorontoPurpose: To determine primary treatment effectiveness, incidence of local tumor progression,and patient survival following radiofrequency ablation (RFA) of unresectable hepatoma (HCC)in a consecutive series of patients not considered candidates for surgical resection.Materials and Methods: At our two hospitals a prospective RFA database has been maintainedsince November 1999. This was analyzed to December 2006 to establish primary treatmenteffectiveness, local tumor progression, and patient survival in HCC. We reviewed 769procedures on 628 tumors in 411 consecutive patients. HCCs were treated with LeVeenelectrodes (Boston Scientific, Natick, MA) n=602 (78.6%); Cool-tip electrodes (TycoHealthcare, Mansfield, MA) n=87 (11.4%); Berchtold electrodes (Integra LifeSciences,Plainsboro, NJ) n=70 (9.1%); and Starburst electrodes (RITA Medical Systems, Fremont, CA)n=7 (0.9%) electrodes. Image guidance was used as follows: ultrasound (US) 39%, CT 14%,CT+US 41%, open US 5% and laparoscopic US 1%. Failure of primary treatment effectivenesswas defined as local viable HCC on the first CT/MRI scan performed >24 hours and

University of Toronto Department of Medical Imaging Research Day 2007Imaging Evolution of Ablation Zones on CT Scanning AfterRadiofrequency Ablation of Liver TumorsSergey Litvin, John R. Kachura, J. Robert Beecroft, C.S. HoUniversity Health Network and Mount Sinai HospitalPurpose: To determine the long-term changes on multiphase CT scanning followingradiofrequency ablation (RFA) of liver tumors.Materials and Methods: Our prospective RFA database for Toronto General Hospital andMount Sinai Hospital was analyzed from November 1999 to September 2006. The patient cohortincluded only those patients with at least 2 years of follow-up post-RFA. Exclusion criteriaincluded patients treated with ethanol injection, transarterial chemoembolization, radiotherapy,or chemotherapy. Clinical features evaluated included tumor type, size, location, adjacentstructures, and electrode used. Features evaluated on annual triphasic CT scans of the liverincluded ablation zone diameter, attenuation on noncontrast, arterial phase and venous phaseimages, rim enhancement, nodular enhancement, and ancillary findings such as adjacent liverparenchymal scarring, calcification, bile duct dilatation, and portal vein branch occlusion.Results: We reviewed 73 tumors in 63 patients. Mean patient age was 64.8 years (range 37 -84). Mean maximum tumor diameter was 2.5 cm (range 0.9 - 4.8). Mean follow-up was 34.6months (range 24 - 70). The ablated tumors were 61 hepatomas (83.6%), 10 colon carcinomametastases (13.7%), a gallbladder carcinoma metastasis (1.4%), and a carcinoid metastasis(1.4%). Ablation zone diameters gradually decreased over time; 5 years after RFA, ablationzone diameters decreased to 61.3% of the one-year post-RFA dimension on average. Attenuationof the ablation zone on noncontrast CT averaged between 42.5 and 44 Hounsfield Units (HU) 1-3 years post-ablation, but then decreased to 31 and 29.7 HU by 4 and 5 years post-RFA,respectively. Ablation zone attenuation was not significantly different on arterial and portalvenous phase imaging. The most frequent ancillary CT finding was adjacent liver parenchymalscarring, with a prevalence of 52% at one year post-RFA and 75% at 5 years post-RFA.Calcification in the ablation zone was noted in 2.9% of tumors at 1 year, and in 25% at year 5post-RFA. Bile duct dilatation and portal vein branch occlusion were seen related to 6% and 4%of tumors, respectively, at 1 year of follow-up, and their prevalence did not significantly changethereafter.Conclusions: Liver tumor ablation zones gradually decrease in size, reaching approximately60% of their one-year post-RFA diameter, 5 years after ablation. Parenchymal scarring adjacentto ablation zones is common after RFA of liver tumors. The prevalence of ablation zonecalcification increases over time, whereas adjacent bile duct dilatation and portal vein branchocclusion are infrequent and non-progressive after 1 year.42 of 54

University of Toronto Department of Medical Imaging Research Day 2007Comparison of Ultrasound Versus Magnetic Resonance Imaging Prior to Uterine ArteryEmbolization in Symptomatic Patients with Presumed Uterine FibroidsRyan Margau*, Dheeraj K. Rajan, Martin E. Simons, Eran B. Hayeems, Ken W. Sniderman,Kongteng Tan, J. Robert Beecroft, John R. KachuraPurpose: To compare the diagnostic utility of ultrasound (US) and magnetic resonance imaging(MRI) of the pelvis on the clinical decision to proceed with uterine artery embolization (UAE).Materials and Methods: Over 2 years, 180 consecutive patients sought consultation for UAE,116 agreed to proceed with imaging and possible UAE. Pre-procedure imaging with transvaginalUS followed by MRI was preformed with prospective data collection. MRI exams occurredwithin 30 days of the initial ultrasound.Results of the pre-procedure US and MRI studies were analyzed for the following; the quantityof uterine fibroids, the size and location of the dominant fibroid, uterine volume and the presenceof potential contraindications to UAE. This included adenomyosis, pedunculated subserosalfibroids, or an alternate diagnosis for the patient s symptoms.Discrepancies between the imaging modalities, and cases where these discrepancies could havealtered clinical management, were recorded.Results: For the 116 patients who completed imaging; average uterine volume by MRI was701cc compared with 658cc by US (p=0.48). The average dominant fibroid volume on MRI was292cc, compared with 253cc on US (p=0.16). In 14 patients (12.1%) US did not correctlyquantify or localize the uterine fibroids compared to MRI (p=0.0005).13 patients did not undergo UAE (9 due to patient preference, 4 due to the pre-procedureimaging findings). In the 4 cases where UAE was not performed due to imaging findings, all(n=4) were diagnosed with MRI and 2 were diagnosed with US (p=0.5); in two cases(adenomyosis n=1, pedunculated subserosal fibroid n=1) the findings were not identified on theUS.103 patients eventually proceeded to UAE. Within this group, MRI identified 14, and ultrasoundidentified 13 patients with potential contraindications to UAE (p=1.0). Despite the presence of apotential contraindication, these 14 patients were embolized without complication.Conclusions: MRI was more accurate than US for the characterization of uterine fibroids. In asmall but statistically insignificant number of cases, US did not identify the presence of apotential contraindication to UAE when compared to MRI.43 of 54

University of Toronto Department of Medical Imaging Research Day 2007Abdominal, GU, GI andMusculoskeletal Imaging44 of 54

University of Toronto Department of Medical Imaging Research Day 2007Small Nodules (10-20 mm) in Liver Cirrhosis: Characterization withContrast-enhanced UltrasoundTae Kyoung Kim 1 , Hyun-Jung Jang 1 , Peter N. Burns 2 , Stephanie R. Wilson 11 Department of Medical Imaging, 2 Departments of Medical Biophysics and Medical Imaging,University of TorontoPurpose: To determine the diagnostic efficacy of arterial-phase (AP) contrast-enhancedultrasound (CEUS) for characterizing small hepatic nodules (10-20 mm) in patients with highriskfor hepatocellular carcinoma (HCC).Materials and Methods: Over 12 months, low-mechanical index (MI) CEUS was performedwith Definity (BMS) in 59 high-risk patients with small hepatic nodules (10-20 mm; mean, 15mm). 31 of them were new nodules seen on surveillance ultrasound and the remaining 28 werenodules referred following multiphasic CT. Based only on AP (< 45s) vascularity, lesions wereprospectively diagnosed as HCC if there was hypervascularity without known features ofhemangioma. The diagnosis of HCC was made regardless of the presence or absence of washoutif hypervascularity was present. Verification of diagnosis was made by liver transplantation(n=13), biopsy (n=12), resection (n=3) or clinical and imaging follow-up for at least 9 months(n=31).Results: At performance of CEUS, the 59 nodules were diagnosed as HCC in 26 and benignlesions in 29, including 16 regenerative/dysplastic nodules (RN/DN), 11 hemangiomas, and 2focal fat sparing. All 26 nodules with AP hypervascularity without hemangioma-like featureswere HCC. However, CEUS misdiagnosed HCC as RN/DN in 4 with arterial iso- (n=3) orhypovascularity (n=1). CEUS correctly diagnosed all 11 hemangiomas. The sensitivity,specificity, and accuracy of CEUS for determining malignancy were 86.7%, 100%, and 93.2%.Conclusions: AP vascularity and pattern alone on CEUS are highly accurate for diagnosis ofsmall hypervascular HCC and hemangioma in liver cirrhosis. HCC should be diagnosed in smallnodules if hypervascularity without a hemangioma-like pattern is shown on CEUS. Infrequentiso/hypovascular HCC may erroneously suggest RN/DN necessitating biopsy or close follow-up.45 of 54

University of Toronto Department of Medical Imaging Research Day 2007Recurrent Hepatocellular Carcinoma: Are Enhancement Features on Contrast-enhancedUltrasound Suggestive of Classic HCC or Metastases?Yang-Yi Ong 1 , Hyun-Jung Jang 1 Tae-Kyoung Kim 1 , Peter N. Burns 2 , Stephanie R. Wilson 11 Department of Medical Imaging, Toronto General Hospital, University of Toronto2 Medical Imaging Research, Sunnybrook and Women’s Health Sciences CenterPurpose: To characterize the appearance and enhancement characteristics of recurrenthepatocellular carcinoma (HCC) following hepatectomy and transplantation with contrastenhanced ultrasound (CEUS), comparing its features with metastases and de novo HCC.Material and Methods: This is a retrospective review of 51 patients, comprising 12 patientswith recurrent HCC following hepatectomy (n=7) and transplantation (n=5), 20 patients with denovo HCC and 19 patients with metastases between January 2003 and August 2006. Two readersindependently reviewed digital cine-clips and static images for time to peak arterialenhancement, pattern of arterial enhancement, time to negative enhancement or washout, patternof washout and degree of washout at 75 and 180 seconds. Inter-reader agreement was assessedusing kappa statistics. Pairwise comparison using Fisher’s exact test was used to assess thestatistical significant difference between the three study groups.Results: There was substantial to almost perfect agreement between the two readers for allvariables assessed (κ = 0.73 – 0.84). There was no statistical difference in the time to peakarterial enhancement between the three groups. All metastases demonstrated washout by 30seconds. De novo HCC had more delayed washout with 12/20 (60%) cases with washout greaterthan 75 seconds. Recurrent HCC showed washout times which was more varied, but skewedtowards earlier washout with 11/12 (92%) and 9/12 (75%) as seen by readers 1 and 2respectively with washout less than 75 seconds.Conclusion: Arterial phase hypervascularity was seen in all three groups. Recurrent HCCappears to be a slightly heterogeneous group tumor with some tumors demonstrating earlierwashout time, more similar to metastases compared with de novo HCC. This suggests that thereis biologically greater spectrum in the degree of tumor differentiation.46 of 54

University of Toronto Department of Medical Imaging Research Day 2007Microcystic Adenomas of the Pancreas : Long-term Follow-up Measurementof Growth RateAlexandre Menard, George Tomlinson, Sean Cleary, Alice Wei, Masoom A HaiderDepartment of Medical Imaging, University Health Network and Mount Sinai Hospital,University of Toronto, Toronto, Ontario, CanadaPurpose: To measure the growth rate of microcystic adenomas of the pancreas diagnosed bycross-sectional imaging.Materials and Methods: Research ethics committee approval was obtained. For thisretrospective study, patient’s reports were searched from 1998 to 2005 for a diagnosis ofmicrocystic adenoma. 241 imaging studies were reviewed. Imaging criteria for microcysticadenoma were 6 or more cysts, all < 2 cm in maximal diameter, no communication withpancreatic duct or pancreatic duct dilatation, no parenchymal calcifications outside of the lesion,and no history of chronic pancreatitis. 31 patients (14 male, 17 female) met these criteria.Growth was assessed by measuring the longest diameter of the lesion. Patient age, sex, lesionlocation, size at presentation, number of cysts, calcification pattern, enhancement pattern andpresence of symptoms at presentation were tested as predictors of growth. Correlations and t-tests were used to assess these relationships. A normal mixture model was used to modelclustering of growth rates.Results: Growth was measured over a mean period of 42 months (range 20-83 months). Therewas a statistically significant (p=0.0004) linear growth of tumor for the entire population. Therewas a significant clustering of the population in two separate growth rates: 0.55 mm/year (n=23)and 5.1 mm/year (n=8) (p=0.001 for test of two groups). Increased diameter of the lesion atpresentation is a significant predictor of rapid growth (r=0.45; p=0.01). Clinical follow-up of 4.2years (range 1.7-7.5 years) was available in 30/31 patients and none had evidence of metastasisor mortality related to pancreatic disease.Conclusion: Imaging diagnosed microcystic adenomas of the pancreas demonstrate two separategrowth rates. Although patient numbers are small, growth did not imply a negative clinicaloutcome.47 of 54

University of Toronto Department of Medical Imaging Research Day 2007Fetal Dural Sinus Malformations—Underrecognized and Underpublished?Author: Dr. Matthew McInnes, 2006-7 UHN Abdominal Imaging Fellow.Supervisor: Dr. Katherine Fong.Co-Authors: Dr. Patrick Shannon, Dr. Susan Blaser, Dr. Ants Toi, Dr. David Chitiyat.Purpose: To evaluate the feasibility and accuracy of prenatal diagnosis of Dural SinusMalformation (DSM).Materials and Methods: The local hospital ethics commitee approved this study. Aretrospective review of the charts of patients seen at the CEOU, Genetics Clinic, and MSHNeuropathology Department between 2002 and 2006 was performed to identify patients with apossible diagnosis of DSM. The clinical, imaging and pathologic features of the patients who fitthe diagnostic criteria for DSM were examined. A literature review was performed on the topicof DSM to evaluate the availability of literature on DSM in Pubmed.Results: Three patients who met the diagositic criteria for DSM were identified. Prenatal USwas performed on all three patients. Prenatal MR was available on 2 patients, and autopsieswere performed on 2 patients. None of the ultrasound, MR or pathology reports mentioned thespecific diagnosis of DSM. The literature review on DSM revealed a paucity of publications inpubmed on DSM. Most of the literature on DSM is not available in Pubmed, but on EMBASE inthe journal Interventional Neuroradiology.Conclusion: DSM is a rare, and often underrecognized entity whose features are amenable tocharacterization by prenatal US and MR. The paucity of readily available literature on DSM maycontribute to its underrecognition.48 of 54

University of Toronto Department of Medical Imaging Research Day 2007Comparison of RECIST (Response Evaluation Criteria in Solid Tumor) Criteriaand Tumor Attenuation in Response to Sunitinib Therapy in Patientswith Metastatic Renal Cell Carcinoma (RCC)P Sarliève, M Atri, G BjarnasonPurpose: RECIST criteria are used to evaluate response to treatment based on sizemeasurement. The purpose of this study is to correlate change in size and tumor attenuation ofmetastatic RCC in patients treated with Sunitinib (Sutent*).Methods and Materials: Twenty-one consecutive patients, 14 men and 7 women, 35-77 yearsof age (58±11), treated with Sunitinib for metastatic RCC were included. One radiologistmeasured size and attenuation of abdominal-pelvic soft tissue metastasis on the same workstationon pre and post treatment enhanced CT. The number of lesions evaluated was based on RECISTcriteria. ROI (Region Of Interest) was placed on the lesions to encompass the lesion alone.Changes in attenuation and size were compared using Wilcoxon signed rank test and McNemar'sChi-squared test. These changes were correlated with PFS (Progression Free Survival) for bothbody and abdomen (Cox proportional hazards model).Results: Time interval between the 2 CTs was 28-111 days (66 ± 24SD). PFS was 15-730 days(IQR:89,226,354 days) for body and 15-788 days (IQR:144,313,448 days) for abdomen.Considering > 20% increase as progressive disease (PD), > 30% decrease as partial response(PR), and

University of Toronto Department of Medical Imaging Research Day 2007Testicular Cancer Surveillance: Standard Versus Low Dose CTME O’Malley, HJ Jang, K Jhaveri, K Khalili, MA Haider, A Panzarella, P Warde, P ChungPurpose: To compare image quality and acceptability of a low dose CT protocol with a standarddose CT protocol of the abdomen and pelvis in patients on surveillance for recurrent testicularcancer.Materials and Methods: This was a prospective study approved by our Research Ethics Board.Informed consent was obtained. All patients were scanned on a Toshiba Aquilion 64 scanner. NoIV contrast was given. The standard dose abdominal/pelvic CT protocol included: acquisition 64x 0.5mm; tube rotation 0.5s; table speed 26.5mm/rotation; kV 120; automatic exposure controlwith minimum/maximum mA 40/440; noise SD 15; reconstruction algorithm FC04; and slicethickness 5/2.5mm. The low dose protocol was the same except: minimum/maximum mA 20/220and noise SD 25.5. For each CT protocol, the Dose Length Product (DLP) was recorded. Theannotation was removed from each set of CT images, and each CT study was randomly assigneda case number. Three readers independently evaluated the images for: image noise anddiagnostic quality using a 5-point scale; and acceptability (acceptable or unacceptable). Thepresence of enlarged lymph nodes (>10mm short axis) was recorded.Results: Forty-seven patients (21-61 years, mean 37 years) had standard and low dose CT scans.Thirty-nine patients had seminoma and 8 patients had non-seminomatous germ cell tumor of thetestis. For standard dose images, the mean image noise and diagnostic quality was scored as3.49, 3.34, 3.72 and 3.74, 3.57, 3.70, for each reader. For low dose images, the mean image noiseand diagnostic quality was scored as 2.45, 2.30, 2.57 and 3.40, 3.00 and 2.83, for each reader.The difference between image noise and diagnostic quality was statistically significant for eachreader when comparing standard and low dose images (P < 0.004). All standard and low dose CTscans were considered acceptable. Two patients had lymphadenopathy indicating recurrentdisease, identified by all 3 readers on both standard and low dose CT scans. The mean DLPs forstandard and low dose CT were 1139 and 508 mGy.cm. The mean dose reduction with low doseCT was 56% (range, 50-63%).Conclusions: Although image noise and diagnostic quality were significantly better withstandard dose CT, all low dose CT scans were considered diagnostically acceptable and recurrentdisease was identified by all reviewers on the low dose CT scans.50 of 54

University of Toronto Department of Medical Imaging Research Day 2007Accuracy of Ultrasound in the Diagnosis of Adnexal TorsionChris DyckSupervisor: Dr. Mostafa AtriIntroduction: Twisting of the vascular pedicle resulting in adnexal torsion is a surgicalemergency requiring immediate medical attention. While establishing a clear diagnosis ofadnexal torsion is critical to prevent irreversible damage and infarction of the ovary, thisdiagnosis may be difficult to establish.Purpose: To test the overall accuracy of ultrasound and to analyze multiple ultrasound findingspreviously described in the literature as being helpful in establishing this diagnosis.Methodology: This is a case-control blinded retrospective study analyzing both pathologicallyproven cases of ovarian torsion (N=17) along with control cases of women who presented tohospital with acute abdominal symptoms (N=45). A chart review was performed to compare theclinical presentation of the two groups. Following this, a consensus review with an AbdominalImaging Staff and Fellow was performed assessing the following ultrasound criteria; ovarian sizeand echogenicity; arterial and venous flow; ovarian position/location; follicle number/position;free abdominal/pelvic fluid; twisted vascular pedicle; adnexal fat.Results: The results of this study suggest that the presenting symptoms alone do not give a clearindication of the presence of adnexal torsion (p > 0.05). However, the ultrasound findings ofovarian enlargement and/or heterogeneous ovarian stromal echogenicity (75%), abnormal arterialor venous flow (81%) or the presence of a twisted pedicle (24%) are reasonably sensitive andhighly specific (98%) for the diagnosis of adnexal torsion. Although follicle distribution withinthe ovary or abnormal echogenicity of the pelvic fat did not appear to be statistically differentbetween the two groups, there seemed to be a statistically insignificant trend suggesting thatabnormal ovarian location may be useful in establishing a diagnosis of adnexal torsion.Conclusion: Overall, ultrasound along with multiple individual ultrasound findings that includeabnormal ovarian blood flow, ovarian enlargement with abnormal echogenicity and the presenceof a twisted vascular pedicle are fairly sensitive and highly specific for establishing the diagnosisof ovarian torsion.51 of 54

University of Toronto Department of Medical Imaging Research Day 2007Alternate Diagnoses in Pre-Embolization Imaging for Fibroids:The Importance of MR ImagingHemi Dua, PGY-3 Diagnostic RadiologySupervisors:Louis Wu, St. Michael’s HospitalAndrew Common, St. Michael’s HosptialIt is of clinical importance to make accurate diagnosis in the pathologic process accountingfor symptoms pre-UAE. Non-fibroid diagnoses such as endometriosis, adenomyosis, orcancer can all act as clinical mimikers. Idenifying these entities may affect the treatmentplan, but more importantly can impact expected outcomes post UAE.The purpose of this study was to demonstrate that the frequency of non-fibroid conditions,which may act as clinical mimickers, is not insignificant. A retrospective review wasconducted of pelvic MRI scans performed at St. Michael’s Hospital between 2004-2006 inall women presenting for UAE consultation with “fibroid”symptomatology. Out of 191women, 53 (28%) had findings consistent with a concurrent or altogether alternative nonfibroiddiagnosis, with resulting outcome implications. The majority of these women(33/53) were diagnosed with adenomyosis, while the remainder demonstrated imagingfeatures in keeping with sarcomas, endometriosis, endometrial polyps, PID, and amiscellaneous “other” category (8, 8, 4, 4, 4, respectively). Eight women had more than onenon-fibroid diagnosis.Although pelvic MRI is frequently performed in many centres pre-UAE as a baseline, ourstudy confirms the utility of this practice and suggests that it is also invaluable in theassessment for fibroid mimickers and, thus, may help to develop the most appropriatetreatment plan with well-informed outcome expectations.52 of 54

University of Toronto Department of Medical Imaging Research Day 2007The Radiographic Quantification of Scapular Winging Following Malunionof Displaced Clavicle Shaft FracturesJennifer Stimec, Dawn Pearce, Jeremy HallIntroduction: The clavicle is one of the most frequently fractured bones in the body.Traditionally, treatment has been based on a conservative approach. However, recent evidencesuggests malunion following displaced clavicle fractures can be associated with scapularwinging and numerous clinical complaints including periscapular pain, shoulder weakness, rapidfatigue, thoracic outlet syndrome, and shoulder asymmetry.Purpose: To identify patients with symptomatic clavicle malunion demonstrating scapularwinging and to radiographically quantify the scapular malposition associated with shortening ofthe clavicle. We identified 14 patients (11 men and 3 women with a mean age of 33 years) whohad a malunion following conservative treatment of a clavicle fracture. Computed tomography(CT) was used to image bilateral shoulder girdles and measurements demonstrated scapularmalposition of 1 cm lateral displacement, 1.6cm superior displacement, 1.4cm anteriortranslation, and 1.2 cm of elevation from the chest wall with 1.7cm of clavicle shortening.Conclusion: Scapular malposition and winging is characteristic and reproducible resultingsecondary to the typical malunited position of the clavicle.53 of 54

University of Toronto Department of Medical Imaging Research Day 2007Department of Medical Imaging Research Day 2007has been made possible bythe generous support of GE Healthcare.54 of 54