In-plane coronary arterial motion velocity: Measurement with electron-beamCT

PURPOSE: To determine the speed of and changes in the speed of coronary art erial movement during the cardiac cycle with electron-beam computed tomogra phy (CT). MATERIALS AND METHODS: With electron-beam CT, 20 consecutive cross:sectiona l images were acquired at the mid right coronary artery (with 50-msec acqui sition time, 8-msec intersection delay, 7-mm section thickness, and intrave nous administration of 40 mL of contrast agent) in 25 patients. On the basi s of the displacement of the left anterior descending, left circumflex, and right coronary arterial cross sections from image to image, movement veloc ity in the transverse imaging plane was calculated and was correlated with the simultaneously recorded electrocardiogram. RESULTS: The velocity of in-plane coronary arterial motion varied considera bly during the cardiac cycle. Peaks were caused by ventricular systole and diastole and by atrial contraction. The mean velocity was 46.6 mm/sec +/- 1 2.5 (SD). The mean velocity of right coronary arterial movement (69.5 mm/se c +/- 22.5) was significantly faster than that of the left anterior descend ing (22.4 mm/sec +/- 4.1) or the left circumflex coronary artery (48.4 mm/s ec +/- 15.0). The lowest mean velocity (27.9 mm/sec) was at 48% of the card iac cycle. CONCLUSION: The lowest velocity of coronary arterial movement, which displa ys considerable temporal variation, was at 48% of the cardiac cycle.