Department of Radiology, Center for Medical Imaging-North East Netherlands, University Medical Center Groningen, University of Groningen, PO Box 30001, 9700RB Groningen, The Netherlands.
Int J Cardiovasc Imaging. 2013 Jun;29(5):1137-48. doi: 10.1007/s10554-012-0176-4. Epub 2013 Jan 17.
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.
计算机断层扫描（CT）可以根据其亨氏单位（HU）来描述富含脂质且可能易于破裂的非钙化冠状动脉粥样硬化斑块，但仍不确定。本研究旨在使用软件模拟评估影响非钙化斑块 HU 值的因素。以 5μm 的分辨率构建了几个现实的虚拟斑块负荷冠状动脉模型。使用类似于 64 排多探测器 CT（64-MDCT）的设置进行 CT 扫描模拟，并以 64-MDCT（0.4mm）和微 CT（48μm）的分辨率进行重建。分析了管腔对比度增强、狭窄程度和斑块成分对斑块可视化的影响。管腔对比度增强与斑块平均 HU 值呈正相关（R²>0.92），对于所有斑块成分，斜率大致相同。脂质含量百分比和斑块平均 HU 值呈负相关（R²>0.98）。狭窄程度和噪声对相关性的影响最小。管腔对比度增强对斑块 HU 值的影响遵循特定的指数衰减模式（y = Ae(-λx) + c），从管腔边界到 2 像素半径。在 2 像素半径之外，斑块 HU 值与非增强参考值相差最大 5HU。因此，为了避免管腔对比度增强的影响，应在距管腔边界 2 像素半径之外测量斑块。基于发现的模式，可以开发出一种管腔影响校正算法。基于 HU 的斑块脂质含量百分比测定可能作为替代斑块特征描述方法。然而，其适用性仍然受到许多固有局限性的阻碍。
