Cardiovascular Magnetic Resonance Measurement of Coronary Arterial Blood Flow at Rest and After Submaximal Exercise

Abstract

These data indicate that cardiovascular magnetic resonance assessments of CABF before and after submaximal exercise are feasible, reproducible, and consistent with those obtained invasively. In future studies, 24 patients would be needed per group to detect a 20% change of submaximal exercise blood flow at 80% power.

Physical Activity in Older Subjects Is Associated With Increased Coronary Vasodilation

“…The measurement of endothelial-dependent vasodilation is challenging in the magnetic resonance environment but deserves further investigation. Reports using the cold pressor test or exercise show promise (41,46), including a recent study showing both impaired vasodilation and blunted flow response to hand-grip exercise in CAD patients (47).…”

Submaximal exercise coronary artery flow increases in postmenopausal women without coronary artery disease after estrogen and atorvastatin

“…The CABF was measured noninvasively with phase-contrast MRI according to previously published techniques 10,11. Magnetic resonance imaging studies were performed on a 1.5-Tesla, GE CV/I whole-body imaging system (General Electric Medical Systems, Waukesha, WI) with participants positioned supine.…”

“…Once the LAD was visualized, we acquired our flow measurement 2.5 cm distal to the origin of the LAD at its bifurcation from the left main coronary artery. Using previously published, reproducibility techniques,10 we utilized methods to locate the same position in the LAD throughout all of the repeat measurements acquired in the study. Magnetic resonance scan parameters included an 8-mm-thick slice, a 256×256 matrix, a 20 cm field of view, a through-plane velocity encoding of 150 cm/s, a 45-degree flip angle, a 13.8 ms repetition time, and a 6.7 ms echo time.…”

“…After 3 flow measurements at rest were obtained (these values were averaged to obtain baseline flow), the participant was withdrawn from the bore to perform submaximal exercise on a nonferromagnetic electronically braked bike (Lode, The Netherlands) 10. To maintain the position of the subject’s torso for repeat artery imaging, the bike was mounted on the end of the MRI table, and the participant pedaled in a supine position.…”

“…To maintain the position of the subject’s torso for repeat artery imaging, the bike was mounted on the end of the MRI table, and the participant pedaled in a supine position. Also, according to previously published techniques, the subjects were marked at the apex of their suprasternal notch to ensure repositioning after exercise 10. After exercising 10 watts for 1 minute, 25 watts for 3 minutes, and 35 to 55 watts for 3 minutes, the subject was advanced back into the scanner, and images and flow measurements were once again taken in the original slice positions used to obtain the flow measurements at rest.…”