Effect of phase-encoding direction upon magnetic resonance image quality of the heart.

In order to optimize overall cardiac image quality on MR images experienced observers were asked to rank and rate MR images of the heart. The effect of phase-encoding direction and use of cardiac triggering with and without respiratory gating was examined in three orthogonal imaging planes. Results indicate that use of both respiratory and cardiac gating yields the best images. Adequate images of the heart can be obtained without respiratory gating. The quality of images of the heart can be optimized by proper selection of the direction of the phase-encoding gradient. These are improved by using horizontal phase encoding in the sagittal plane and vertical phase encoding in transverse and coronal planes.