Feasibility and performance of breath-hold 3D TRUE-FISP coronary MRA using self-calibrating parallel acquisition

Spatial resolution in 3D breath-hold coronary MR angiography (MRA) is limited by imaging time. The purpose of this work was to investigate the feasibility of improving the spatial resolution of coronary MRA using generalized autocalibrating partially parallel acquisition (GRAPPA) and fast imaging with steady state precession (True-FISP) data acquisition. Coronary data were acquired in 10 healthy volunteers. In five volunteers, the data were fully acquired in k-space and decimated for GRAPPA with an outer reduction factor (ORF) of 2. The coil calibration in GRAPPA was improved by segmented least-squares fitting along the frequency-encoding direction. More than 5% of the total k-space lines were required for the calibration to achieve acceptable artifact suppression despite slightly lower signal-to-noise ratio (SNR). In another five volunteers, coronary data were obtained with both conventional and accelerated data acquisitions in the same imaging time. GRAPPA allowed a submillimeter in-plane resolution, and improved coronary artery definition with an acceptable loss of SNR. In conclusion, 3D breath-hold coronary MRA by GRAPPA and True-FISP is highly feasible.