Coronary artery stenosis-related perfusion ratio using dynamic computed tomography myocardial perfusion imaging: a pilot for identification of hemodynamically significant coronary artery disease

Abstract

The purpose of this study was to evaluate the feasibility of the stenosis-related quantitative perfusion ratio (QPR) for detecting hemodynamically significant coronary artery disease (CAD). Twenty-seven patients were retrospectively enrolled. All patients underwent dynamic myocardial computed tomography perfusion (CTP) and coronary computed tomography angiography (CTA) before invasive coronary angiography (ICA) measuring the fractional flow reserve (FFR). Coronary lesions with FFR ≤ 0.8 were defined as hemodynamically significant CAD. The myocardial blood flow (MBF) was calculated using dynamic CTP data, and CT-QPR was calculated as the CT-MBF relative to the reference CT-MBF. The stenosis-related CT-MBF and QPR were calculated using Voronoi diagram-based myocardial segmentation from coronary CTA data. The relationships between FFR and stenosis-related CT-MBF or QPR and the diagnostic performance of the stenosis-related CT-MBF and QPR were evaluated. Of 81 vessels, FFR was measured in 39 vessels, and 20 vessels (51%) in 15 patients were diagnosed as hemodynamically significant CAD. The stenosis-related CT-QPR showed better correlation (r = 0.70, p < 0.05) than CT-MBF (r = 0.56, p < 0.05). Sensitivity and specificity for detecting hemodynamically significant CAD were 95% and 58% for CT-MBF, and 95% and 90% for CT-QPR, respectively. The area under the receiver operating characteristic curve for the CT-QPR was significantly higher than that for the CT-MBF (0.94 vs. 0.79; p < 0.05). The stenosis-related CT-QPR derived from dynamic myocardial CTP and coronary CTA showed a better correlation with FFR and a higher diagnostic performance for detecting hemodynamically significant CAD than the stenosis-related CT-MBF.

Computed tomographic evaluation of myocardial ischemia

“…However, the optimal quantification method remains controversial and the cut-off value on dynamic CTP imaging is still not standardized. Recently, relative flow reserve has been shown to be a better alternative to absolute MBF [40,65,66]. CFR is calculated as a quantitative ratio of stress MBF to rest MBF in stress and rest dynamic CTP protocol [36].…”

Combined assessment of subtended myocardial volume and myocardial blood flow for diagnosis of obstructive coronary artery disease using cardiac computed tomography: A feasibility study

“…Sixth, a disagreement in the scan phase between CTA and CTP might cause a misregistration for the 3-dimensional imposition of two postprocessing datasets of CTA and CTP. In the present study, the nonrigid registration was used to adjust the misregistration, and the 3dimensional integration of coronary CTA and CT-MBF was successfully performed in all patients as well as a recent study [22]. However, Voronoi diagram-based myocardial segmentation strongly depends on the accuracy of coronary CTA tree.…”

“…Recently, Voronoi diagram-based myocardial segmentation using coronary CTA has been available in clinical research, which allowed for the calculation of the CT-MBFsub and V sub for each coronary artery lesion [8,22]. Theoretically, CT-MBFsub was expected to be more advantageous than standard CT-MBF because it can accurately reflect the perfusion territory of each coronary artery in individual cases.…”

Diagnostic accuracy of stress myocardial computed tomography perfusion imaging to detect myocardial ischemia: a comparison with coronary flow velocity reserve derived from transthoracic Doppler echocardiography

“…Alternatively, CT-MBF can be assessed by manually placed regions of interest, while MBF also varies between individuals for various clinical conditions. Reported MBF cut-off values vary substantially from 0.75 to 1.64 mL/g/min between studies [29,30]. Physicians should pay attention to the perfusion territory by targeted vessels or branches in the interpretation of myocardial ischemia with the two techniques.…”

“…In addition, for TTDE-derived CFVR measurement, some difficulties remain in assessing the anatomical locations of stenotic lesions and the related myocardial territories in the RCA or LCX. If applying an automatic quantitative method of coronary artery-based myocardial segmentation on CT [30,31], the diagnostic performance of multi-vessel disease can be assessed. Fourth, various factors might affect MBF [32].…”