Incremental value of volumetric quantification for myocardial perfusion imaging by computed tomography

Abstract

Background:The extent of myocardial ischemia is the crucial prognostic factor for interventional treatment decision making for coronary artery disease. The ability of computed tomography perfusion (CTP) to provide the missing volumetric information and its clinical value remains unknown. Aims:The study aimed to compare a novel ischemic volume quantification method based on dynamic computed tomography perfusion (VOL CTP) with other CT-based imaging modalities for revascularization prediction. Methods:In this prospective study, 53 (25 females, 63.5 [8.5] years old) consecutive symptomatic patients with 50%-90% coronary artery stenosis (n ≥1) on coronary computed tomography angiography underwent computed-tomography-derived fractional flow reserve (CT-FFR) analysis and dynamic CTP. We calculated the percentage of myocardial ischemia on the CTP-derived images. A 10% cut-off was used to define functionally significant ischemia. The outcomes include coronary revascularization during the follow-up of 2.5 (interquartile range, 1.4-2.8) years. Physicians were blinded to the results of CTP and CT-FFR. Results:Of the 53 patients in the study (68 arteries with 50%-90% stenosis), 16 underwent revascularization (12 elective, 4 event-driven). In the CTP quantitative analysis, 26 patients had ischemia. Overall, 18 patients had ischemia ≥10% on volumetric ischemia quantification based on dynamic computed tomography perfusion (VOL CTP), and 28 patients had CT-FFR <0.8. VOL CTP, standard CTP, CT-FFR, and computed tomography coronary angiography (CTA) ≥70% performed well for the prediction of total revascularization. Area under the curve was 0.973 vs. 0.865, vs. 0.793, vs. 0.668, respectively. The VOL CTP with ≥10% cut-off was superior to the CT-FFR, standard CTP, and CTA ≥70% (P <0.001; P = 0.002 and P <0.001 respectively).Conclusions: VOL CTP quantification is feasible and adds important, actionable information to that provided by standard CTP or CT-FFR in patients with 50%-90% coronary artery stenosis.