Department of Radiology, Medical University of Vienna, Vienna General Hospital, 18-20 Waehringer Guertel, Vienna, 1090 Austria.
AJR Am J Roentgenol. 2013 Aug;201(2):W227-34. doi: 10.2214/AJR.12.9453.
The purpose of this study was to use second-generation dual-source CT to assess the influence of size, degree of stenosis, luminal contrast attenuation, and plaque geometry on stenosis quantification in a coronary artery phantom.
Six vessel phantoms with three outer diameters (2, 3, and 4 mm), each containing three radiolucent plaques (72.2 HU) that simulated eccentric and concentric 43.8%, 75%, and 93.8% stenoses were made with a 3D printer system. These phantoms were filled with an iodine-saline solution mixture at luminal attenuations of 150, 200, 250, 300, and 350 HU and were attached to a cardiac motion simulator. Dual-source CT was performed with a standardized ECG-gated protocol (120 kV, 360 mAs per rotation) at a simulated heart rate of 70 beats/min. Two independent readers quantified the degree of stenosis using area-based measurements.
All measurements were highly reproducible (intraclass correlation, ≥ 0.791; p < 0.001). The mean measured degree of stenosis for a phantom with a 3-mm outer diameter at 250-HU luminal attenuation was 49.0% ± 10.0% for 43.8% stenosis, 71.7% ± 9.6% for 75.0% stenosis, and 85.4% ± 5.9% for 93.8% stenosis. With decreasing phantom size, measurement error increased for all degrees of stenosis. The absolute error increased for measurements at a low luminal attenuation of 150 HU (p < 0.001) and for low-grade stenoses compared with medium-and high-grade stenoses (p < 0.001).
The results are an overview of factors that influence stenosis quantification in simulated coronary arteries. Dual-source CT is highly reproducible and accurate for quantification of low-density stenosis in vessels with a diameter of 3 mm and attenuation of at least 200 HU for different degrees of stenosis and plaque geometry.
本研究旨在使用第二代双源 CT 评估在冠状动脉模型中，斑块大小、狭窄程度、管腔对比度衰减和斑块形态对狭窄定量的影响。
使用 3D 打印机系统制作了六个外直径分别为 2、3 和 4mm 的血管模型，每个模型均包含三个模拟偏心和同心狭窄程度为 43.8%、75%和 93.8%的透光斑块，这些模型的斑块用碘盐水溶液混合物填充，管腔衰减值为 150、200、250、300 和 350HU，并附着在心脏运动模拟器上。双源 CT 采用标准化 ECG 门控协议（每个旋转 120kV，360mAs），模拟心率为 70 次/分钟。两名独立的读者使用基于面积的测量方法定量测量狭窄程度。
所有测量结果均具有高度可重复性（组内相关系数≥0.791；p<0.001）。在 250HU 管腔衰减下，3mm 外直径的模型中，43.8%狭窄的平均测量狭窄程度为 49.0%±10.0%，75.0%狭窄的平均测量狭窄程度为 71.7%±9.6%，93.8%狭窄的平均测量狭窄程度为 85.4%±5.9%。随着模型尺寸的减小，所有狭窄程度的测量误差都增加。与中、高度狭窄相比，在低管腔衰减（150HU）和低级别狭窄时，测量的绝对误差增加（p<0.001）。
该研究结果概述了影响模拟冠状动脉狭窄定量的因素。对于不同程度狭窄和斑块形态的 3mm 直径和至少 200HU 衰减的血管，双源 CT 对低密度狭窄的定量具有高度的可重复性和准确性。
