Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117, Berlin, Germany.
Department of Radiology, Mie University Graduate School of Medicine, Mie, Japan.
Sci Rep. 2022 Mar 24;12(1):5085. doi: 10.1038/s41598-022-09144-6.
Fractal analysis of dynamic, four-dimensional computed tomography myocardial perfusion (4D-CTP) imaging might have potential for noninvasive differentiation of microvascular ischemia and macrovascular coronary artery disease (CAD) using fractal dimension (FD) as quantitative parameter for perfusion complexity. This multi-center proof-of-concept study included 30 rigorously characterized patients from the AMPLIFiED trial with nonoverlapping and confirmed microvascular ischemia (n = 10), macrovascular CAD (n = 10), or normal myocardial perfusion (n = 10) with invasive coronary angiography and fractional flow reserve (FFR) measurements as reference standard. Perfusion complexity was comparatively high in normal perfusion (FD = 4.49, interquartile range [IQR]:4.46-4.53), moderately reduced in microvascular ischemia (FD = 4.37, IQR:4.36-4.37), and strongly reduced in macrovascular CAD (FD = 4.26, IQR:4.24-4.27), which allowed to differentiate both ischemia types, p < 0.001. Fractal analysis agreed excellently with perfusion state (κ = 0.96, AUC = 0.98), whereas myocardial blood flow (MBF) showed moderate agreement (κ = 0.77, AUC = 0.78). For detecting CAD patients, fractal analysis outperformed MBF estimation with sensitivity and specificity of 100% and 85% versus 100% and 25%, p = 0.02. In conclusion, fractal analysis of 4D-CTP allows to differentiate microvascular from macrovascular ischemia and improves detection of hemodynamically significant CAD in comparison to MBF estimation.
分形分析动态四维计算机断层心肌灌注（4D-CTP）成像可能具有使用分形维数（FD）作为灌注复杂性的定量参数，无创区分微血管缺血和大血管冠状动脉疾病（CAD）的潜力。这项多中心概念验证研究纳入了来自 AMPLIFiED 试验的 30 名严格特征化的患者，这些患者无重叠且经确认存在微血管缺血（n=10）、大血管 CAD（n=10）或正常心肌灌注（n=10），以有创冠状动脉造影和血流储备分数（FFR）测量作为参考标准。正常灌注的灌注复杂性较高（FD=4.49，四分位距[IQR]：4.46-4.53），微血管缺血时中度降低（FD=4.37，IQR：4.36-4.37），大血管 CAD 时显著降低（FD=4.26，IQR：4.24-4.27），这使得两种缺血类型得以区分，p<0.001。分形分析与灌注状态高度一致（κ=0.96，AUC=0.98），而心肌血流（MBF）显示出中度一致性（κ=0.77，AUC=0.78）。对于检测 CAD 患者，分形分析的敏感性和特异性为 100%和 85%，优于 MBF 估计的敏感性和特异性为 100%和 25%，p=0.02。总之，与 MBF 估计相比，4D-CTP 的分形分析可区分微血管与大血管缺血，并提高对血流动力学意义重大的 CAD 的检测。
