Diagnostic value of quantitative coronary flow reserve and myocardial blood flow estimated by dynamic 320 MDCT scanning in patients with obstructive coronary artery disease

We have developed the method for dynamic 320-row multidetector computed tomography (MDCT)-derived quantitative coronary flow reserve (CFR(CT)) and hyperemic myocardial blood flow (MBF(CT)). We evaluated diagnostic value of CFR(CT) and hyperemic MBF(CT) for detecting obstructive coronary artery disease (CAD) in per-patient and per-vessel analysis, and their relations with the severity of CAD burden. Adenosine stressed and rest dynamic myocardial perfusion MDCT were prospectively performed in patients with known or suspected CAD. Per-patient and per-vessel MBF(CT) were estimated from dynamic perfusion images in rest and hyperemic phases, and per-patient and per-vessel CFR(CT) were calculated from the ratio of rest and hyperemic MBF(CT). Degree of stenosis was evaluated by coronary CT angiography (CTA) and invasive coronary angiography (ICA). Obstructive stenosis was defined as ≥70% stenosis in ICA. CAD burden with MDCT was calculated by logarithm transformed coronary artery calcium (CAC) score and the CTA-adapted Leaman risk score (CT-LeSc). A logistic regression analysis was used to measure the receiver-operating characteristic curve and corresponding area under the curve (AUC) for the detection of obstructive CAD. Twenty-seven patients and 81 vessels were eligible for this study. Sixteen patients had obstructive CAD, and 31 vessels had obstructive stenosis. Using an optimal cutoff, the CFR(CT) and hyperemic MBF(CT) had the moderate diagnostic values in per-patient (AUC = 0.89 and 0.86, respectively) and per-vessel (AUC = 0.79 and 0.76, respectively). Per-patient CFR(CT) and hyperemic MBF(CT) exhibited a moderate inverse correlation with CAC score and the CT-LeSc. Per-patient and per-vessel CFR(CT) as well as hyperemic MBF(CT) had moderate diagnostic value for detecting obstructive CAD. These per-patient values exhibited a moderate inverse correlation with CAD burden. CFR(CT) and hyperemic MBF(CT) might add quantitative functional information for evaluating patients with CAD.