title: Non-calcified coronary atherosclerotic plaque visualization on CT: effects of contrast-enhancement and lipid-content fractions.
abstract: Computed tomography (CT) may characterize lipid-rich and presumably rupture-prone non-calcified coronary atherosclerotic plaque based on its Hounsfield-Unit (HU), but still inconclusively. This study aimed to evaluate factors influencing the HU-value of non-calcified plaque using software simulation. Several realistic virtual plaqueburdened coronary phantoms were constructed at 5 μm resolution. CT scanning was simulated with settings resembling a 64-row multi-detector CT (64-MDCT) and reconstructed at 64-MDCT (0.4 mm) and MicroCT (48 μm) resolutions. Influences of lumen contrast-enhancement, stenosis-grades, and plaque compositions on plaque visualization were analyzed. Lumen contrast-enhancement and mean plaque HU-value were positively correlated (R(2) > 0.92), with approximately the same slopes for all plaque compositions. Percentage lipid-content and mean plaque HU-value were negatively correlated (R(2) > 0.98). Stenosis-grade and noise had minimal influence on the correlations. Influence of lumen contrast-enhancement on plaque HU-value was following a specific exponentially declining pattern (y = Ae(-λx) + c) from the lumen border until 2-pixel radius. Outside 2-pixel radius, plaque HU-values deviated maximally 5 HU from non-contrast-enhanced reference. Thus, to avoid lumen contrast-enhancement influence, plaques should be measured outside 2-pixel radius from the lumen border. Based on the patterns found, a lumen influence correction algorithm may be developed. HU-based plaque percentage lipid-content determination might serve as an alternative plaque characterization method. However, its applicability is still hindered by many inherent limitations.
authors: Department of Radiology, Center for Medical Imaging-North East Netherlands, University Medical Center Groningen, University of Groningen, PO Box 30001, 9700RB Groningen, The Netherlands.
authors: Wisnumurti
authors: W
authors: Kristanto
authors: Peter M A
authors: PM
authors: van Ooijen
authors: Marcel J W
authors: MJ
authors: Greuter
authors: Jaap M
authors: JM
authors: Groen
authors: Rozemarijn
authors: R
authors: Vliegenthart
authors: Matthijs
authors: M
authors: Oudkerk
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D017023:Coronary Angiography / Q000295:instrumentation / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000378:metabolism; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000378:metabolism; D003331:Coronary Vessels / Q000737:chemistry / Q000000981:diagnostic imaging*; D006801:Humans; D016014:Linear Models; D008055:Lipids / Q000032:analysis*; D008955:Models, Cardiovascular; D061330:Multidetector Computed Tomography / Q000295:instrumentation; D019047:Phantoms, Imaging; D058226:Plaque, Atherosclerotic; D011237:Predictive Value of Tests; D012720:Severity of Illness Index; D012984:Software
chemical_list: D008055:Lipids