Coronary flow reserve: Noninvasive measurement in humans with breath-hold velocity-encoded cine MR imaging

PURPOSE: To measure coronary vasodilator reserve with breath-hold velocity-encoded cine magnetic resonance (MR) imaging. MATERIALS AND METHODS: Eight healthy adult volunteers underwent 1.5-T MR imaging. Velocity-encoded cine images were acquired at seven to 13 temporal phases in 25 seconds, with k-space segmentation and view-sharing reconstruction (±1 m/sec velocity- encoding value) (repetition time msec/echo time msec = 16/9). Flow velocity in the left anterior descending (LAD) artery was measured twice before and twice after administration of dipyridamole (0.56 mg per kilogram of body weight). RESULTS: Peak diastolic coronary flow velocity in the LAD artery was 14.8 cm/sec ± 1.9 (mean ± standard deviation) in the baseline state. It increased significantly (P <.01) to 46.3 cm/sec ± 10.2 after dipyridamole administration, with an average coronary reserve of 3.14 ± 0.59. Interstudy and interobserver reproducibilities for measurement of peak diastolic velocity were, respectively, 9.5% ± 1.6 and 7.0% ± .2.5 in the baseline state and 6.8% ± 2.2 and 3.4% ± 1.5 after dipyridamole administration. CONCLUSION: Breath-hold velocity-encoded cine MR imaging provided reproducible assessment of coronary flow reserve in humans.