Direct comparison of 3D spiral vs. Cartesian gradient-echo coronary magnetic resonance angiography

While 3D thin-slab coronary magnetic resonance angiography (MRA) has tradit ionally been performed using a Cartesian acquisition scheme, spiral k-space data acquisition offers several potential advantages. However, these strat egies have not been directly compared in the same subjects using similar me thodologies. Thus, in the present study a comparison was made between 3D co ronary MRA using Cartesian segmented k-space gradient-echo and spiral k-spa ce data acquisition schemes. In both approaches the same spatial resolution was used and data were acquired during free breathing using navigator gati ng and prospective slice tracking. Magnetization preparation (T-2 preparati on and fat suppression) was applied to increase the contrast. For spiral im aging two different examinations were performed, using one or two spiral in terleaves, during each R-R Interval. Spiral acquisitions were found to be s uperior to the Cartesian scheme with respect to the signal-to-noise ratio ( SNR) and contrast-to-noise-ratio (CNR) (both P < 0.001) and image quality. The single spiral per R-R interval acquisition had the same total scan dura tion as the Cartesian acquisition, but the single spiral had the best image quality and a 2.6-fold increase in SNR. The double-interleaf spiral approa ch showed a 50% reduction in scanning time, a 1.8-fold increase in SNR, and similar image quality when compared to the standard Cartesian approach. Sp iral 3D coronary MRA appears to be preferable to the Cartesian scheme. The increase in SNR may be "traded" for either shorter scanning times using mul tiple consecutive spiral interleaves, or for enhanced spatial resolution. ( C) 2001 Wiley-Liss, Inc.