Diagnosing myocardial ischemia of obstructive coronary artery disease using dynamic computed tomography myocardial perfusion imaging: optimization of relative myocardial blood flow ratio

To compare the diagnostic efficacy of different relative myocardial blood flow (MBF) ratios in computed tomography perfusion (CTP) for myocardial ischemia in patients with obstructive coronary artery disease (CAD).

Between October 2020 and March 2024, patients with suspected or known obstructive CAD who underwent CTP + coronary computed tomography angiography and invasive coronary angiography/fractional flow reserve were retrospectively selected. Patients and vessels were categorized into ischemia and non-ischemia groups. The diagnostic efficacies of the three relative MBF ratios were compared in patients with obstructive CAD.

This study included 48 patients (144 vessels). Notably, 34 of the 48 patients (70.83%) and 49 of the 144 vessels (34.03%) were considered to have myocardial ischemia. The area under the curve of Ratio-hi (0.944, 95% confidence interval: 0.893–0.976) was higher than those of Ratio-av, Ratio-Q3, and MBF-lowest; However, no statistical differences were found (P>0.005). The cutoff value for detecting Ratio-hi was 0.667, and the sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were 91.8%, 83.2%, 75%, 95.24%, and 86.81%, respectively.

Relative MBF ratios, especially Ratio-hi, demonstrated excellent performance and exhibited greater robustness in diagnosing myocardial ischemia in patients with obstructive CAD.