Scientific Report 2003-2004 - Cleveland Clinic Lerner Research ...

THE WHITAKERBIOMEDICAL IMAGINGLABORATORYTHE VINCELABORATORYINVESTIGATORSDevyani Bedekar, B.S.Jon D. Klingensmith, Ph.D.Barry D. Kuban, B.S.Anuja Nair, B.Eng., Ph.D.COLLABORATORSAaron J. Fleischman, Ph.D. 1Steven E. Nissen, M.D. 2Shuvo Roy, Ph.D. 1E. Murat Tuzcu, M.D. 21Dept. of BiomedicalEngineering, CCF2Dept. of CardiovascularMedicine, CCFIntravascular ultrasound (IVUS) is becomingaccepted as an imaging technique that allowsprecise tomographic assessment of thecoronary artery anatomy in vivo. Clinical studieshave documented the sensitivity of IVUS indetecting atherosclerosis and in quantifying themorphology of coronary arterial lesions. Moreimportantly, IVUS can potentially quantify thestructure and composition of normal andatherosclerotic coronary arteries in the clinicalsetting rather than relying on histological data,which can only be obtained at autopsy.Many studies evaluating the efficacy ofIVUS in determining plaque composition havebeen limited by theirreliance on digitizingvideotape, which hasthree major limitations:(1) it is verytime consuming andtherefore not feasiblefor near real-timeanalysis; (2) it reducesthe resolution of theimage to that ofvideotape (approximately330 µm); and(3) parameters such asgain and intensity canbe adjusted by the operator, thereby addingvariability to the data set. More recent studieshave realized the importance of gaining access tothe ultrasound backscattered signal, often referredto as the radiofrequency (RF) signal or “backscatter”.Spectral analysis of the unprocessedultrasound signal allows a more detailed interro-The Department of Biomedical EngineeringIntravascular Ultrasound Offers InnovativeView on Atherosclerotic Plaque Buildupand Treatment Strategy OptionsTHETHEVINCELABO-RAgation of various vessel components thandigitization of videotape.We have developed software that usesspectral analysis methods to determine plaquecomposition from IVUS images and display a“Virtual Histology” map. This analysis tool hasbeen licensed to Volcano Therapeutics (LagunaHills, CA) and is currently undergoing trials inEurope.Harmonic ImagingOver the past several years, the technologyfor IVUS, in response to clinical pressure, hasmoved towards lower-profile probes withimproved handling. Not only does a lower-profileprobe allow one to exploremore of the coronary tree,but it is also less likely todisturb potentially unstableplaque at a stenosis site.Intravascumovtowardslower-profiprobes withImage quality has beenmuch less an issue thancatheter profile, and in fact,newer catheters usingsmaller, unfocused elementsactually offer poorerimaging performance thantheir predecessors.In collaboration withDrs. Shuvo Roy and Aaron Fleischman, wepropose to design and build high-frequencyultrasound transducers comprising traditionalceramic and novel polymeric materials fabricatedusing MEMS technology. The ability of thesetransducers to be used for high-frequencyharmonic imaging will be assessed.D. Geoffrey Vince, Ph.D.Nair, A., Kuban, B.D., Tuzcu, E.M., Schoenhagen, P., Nissen, S.E., and D.G. Vince (2002) Coronaryplaque classification using intravascular ultrasound radiofrequency data analysis. Circulation 106:2200-2206.Klingensmith, J.D., and D.G. Vince (2002) B-spline Methods for interactive segmentation and modeling oflumen and vessel surfaces in three-dimensional intravascular ultrasound. Comput. Med. Imaging Graph. 26429-438.Tajaddini, A., Kilpatrick, D., and D.G. Vince (2002) A Novel Experimental Method to Estimate Stress-StrainBehavior of Intact Coronary Arteries Using Intravascular Ultrasound (IVUS). Journal of Biomechanical Engineering125(1):120-123, 2002Klingensmith, J.D., Tuzcu, E.M., Nissen, S.E., and D.G. Vince (2003) Validation of an automated systemfor luminal and medial adventitial border detection in three-dimensional Intravascular ultrasound. Int. J.Cardiovasc. Imaging 19:93-104.Vince, D.G., Nair, A., Klingensmith, J.D., Moore, M.P., and V. Burgess (2003) Radiofrequency tissue characterization.In: Waksman R, Serruys P, eds. Handbook of the Vulnerable Plaque. London: Martin DunitzLtd., 2003.30