Superiority of prone position in free-breathing 3D coronary MRA in patients with coronary disease

Navigator-gated and corrected 3D coronary MR angiography (MRA) allows submi llimeter image acquisition during free breathing. However, cranial diaphrag matic drift and relative phase shifts of chest-wall motion are limiting fac tors for image quality and scanning duration. We hypothesized that image ac quisition In the prone position would minimize artifacts related to chest-w all motion and suppress diaphragmatic drift. Twelve patients with radiograp hically-confirmed coronary artery disease and six healthy adult volunteers were studied in both the prone and the supine position during free-breathin g navigator-gated and corrected 3D coronary MRA. Image quality and the diap hragmatic positions were objectively compared. In the prone position, there was a 36% improvement in signal-to-noise ratio (SNR; 15.5 +/- 2.7 vs. 11.4 +/- 2.6; P < 0.01) and a 34% improvement in CNR (12.5 +/- 3.3 vs. 9.3 +/- 2.5, P < 0.01). The prone position also resulted in a 17% improvement in co ronary vessel definition (P < 0.01). Cranial end-expiratory diaphragmatic d rift occurred less frequently in the prone position (23% +/- 17% vs. 40% +/ - 26% supine; P < 0.05), and navigator efficiency was higher. Prone coronar y MRA results in improved SNR and CNR with enhanced coronary vessel definit ion. Cranial end-expiratory diaphragmatic drift also was reduced, and navig ator efficiency was enhanced. When feasible, prone imaging Is recommended f or free-breathing coronary ATRA. (C) 2001 Wiley-Liss, Inc.