基于冠状动脉形状阻力的血流储备分数数值模拟

目的构建一种将狭窄形状阻力作为边界条件的无创计算血流储备分数(FFRCT)的方法,检验其计算准确性。方法取16例患者冠状动脉CT血管造影图像进行三维重建;考虑狭窄最小横截面积、狭窄长度构建形状阻力的数学模型,并以此造成的压力差作为边界条件加载到FFRCT计算中(简称形状阻力法)。以临床FFR值作为金标准,从平均误差率、准确率、敏感性以及阳性、阴性预测率5个方面,对照以往的管径法和体积法,分析形状阻力法的准确性。结果基于管径法、体积法、形状阻力法计算FFRCT平均误差率分别为11.76%、10.46%、4.82%,准确率分别为85%、65%、90%,敏感性分别为85.7%、66.7%、87.5%,阳性预测率分别为75%、25%、87.5%,阴性预测率均为91.6%。结论从平均误差率、准确率、敏感性、阳性预测率方面,所建立的形状阻力法均优于管径法和体积法,形状阻力法计算的FFRCT与临床实测FFR具有良好的一致性,为FFRCT的计算和应用提供一种新方法。

Numerical Simulation of Fractional Flow Reserve Based on Shape Resistance of Coronary Artery

Objective To establish a method for non-invasive calculation of fractional flow reserve (FFRCT) with the shape resistance of coronary artery stenosis as boundary condition, and to verify the accuracy of this method. Methods CT angiography images of 16 patients with coronary artery disease were reconstructed; the mathematical model of shape resistance was established by considering the minimum cross-sectional area and the length of stenosis of coronary artery stenosis, the induced pressure difference as the boundary condition was applied to calculate FFRCT (named as shape resistance method ). The values of clinical FFR were taken as the gold standard, previous diameter method and volume method were taken as control method, and accuracy of shape resistance method was investigated from the aspects of mean error rate, accuracy rate, sensitivity rate, positive prediction rate and negative prediction rate. Results The mean error rate of calculated FFRCT by the diameter method, volume method and shape resistance method were 11.76%, 10.46%, 4.82%, the accuracy rates were 85%, 65%, 90%, the sensitivity rates were 87.5%, 66.7%, 87.5%, the positive prediction rate were 75%, 25%, 87.5%, respectively, while the negative prediction rates were all 91.6%. Conclusions The established shape resistance method is better than the diameter method and volume method from the aspects of mean error rate, accuracy rate, sensitivity rate and positive prediction rate; the FFRCT based on the shape resistance method and clinical FFR have good consistency, and this work may provide a new way for the calculation and application of FFRCT.