Myocardial Perfusion Defect in Patients With Coronary Artery Disease Demonstrated by 64-Multidetector Computed Tomography at Rest

Background: The first-pass imaging of 64-multidetector computed tomography (MDCT) using pharmacological stress has been used to assess myocardial perfusion. However, detection of myocardial ischemia at rest using MDCT has yet to be elucidated. We studied the incidence of myocardial perfusion defect (MPD) by 64-MDCT at rest and the effect of coronary revascularization therapy on MPD in patients with coronary artery disease. Hypothesis: MPD by 64-MDCT at rest indicates myocardial ischemia. Methods: We studied 76 patients with coronary artery disease who underwent 64-MDCT before and after revascularization therapy and 55 patients who did not undergo revascularization therapy. According to percent diameter stenosis, we defined group A, B, C, and D to have stenosis between 70% and 90%, 50% and 69%, 30% and 49%, and 10% and 29%, respectively. We evaluated regional myocardial contrast enhancement by long and short axis planes. MPD was defined as hypoenhancement area of some extent with CT value <50 HU during diastole. Results: MPD was found in 60.0% and 32.4% of group A and B patients, respectively (P = 0.0176). The incidence was 4.8% and 0% in group C and D patients, respectively (P < 0.0001 compared with group A and B). All patients in group A and B and 2 patients with MPD in group C underwent coronary revascularization therapy. MPD disappeared after revascularization therapy in all but 3 group A patients. No patients showed new MPD after revascularization therapy. Conclusions: Our results demonstrate that a significant percentage of patients with significant coronary artery stenosis show MPD by 64-MDCT at rest, and these MPDs may represent myocardial ischemia.