Myocardial Perfusion Magnetic Resonance Imaging for Diagnosing Coronary Arterial Stenosis

Abstract

SUMMARYIt has been reported that myocardial perfusion MRI is a useful method for evaluating the severity of myocardial ischemia. We evaluated whether the severity of coronary arterial stenosis could be assessed by the signal-intensity time curve (SITC) obtained by myocardial perfusion MRI.The subjects consisted of 10 patients who showed no abnormalities on coronary angiographies (CAG) (A group), 12 with single-vessel disease of 75-90% stenosis on CAG (B group), and 15 with single-vessel disease of 90% or more stenosis (C group). After infusion of dipyridamole for 4 minutes, gadolinium-diethylenetriamine pentaacetic acid was administered intravenously, followed by serial acquisition of T1-weighted left ventricular short-axis MR images. These images were evaluated after dividing them into the following 3 myocardial segments: anterior wall, lateral wall, and inferior wall. Mean values of the slope of SITC (1.4 ± 0.2 vs 1.1 ± 0.2, P < 0.01), and increases to the peak corrected SI (∆SI) (47.5 ± 1.9 % vs 33.7 ± 2.4%, P < 0.01) in normal myocardial segments were significantly greater than in ischemic segments in the C group, while there was no significant distinction between normal and ischemic segments in the B group. The mean values of time to the peak SI were not significantly different between normal and ischemic regions in the B and C groups.The results suggest that myocardial segments exhibiting 30% decreases in both the slope and ∆SI of SITC can be diagnosed as having 90% or more severe coronary stenosis.The present study shows that visual and SITC evaluations of myocardial perfusion MR images may be useful for clinically evaluating the severity of coronary stenosis. (Jpn Heart J 2003; 44: 323-334)