Rapid 5-minute Echo-Planar Spectroscopic Imaging of Prostate Cancer Patients at 3T

Introduction Proton spectroscopic imaging of the prostate has become a valuable clinical tool due to its effectiveness in detecting the presence and aggressiveness of prostate tumors [1]. However, the long acquisition times (typically 15-20 minutes) for the 3D phase encoding traditionally employed can be prohibitively long. A flyback echo-planar readout sequence has been developed and recently implemented for our clinical cases at UCSF. This sequence necessitates only 2 dimensions of spatial phase encoding, thus drastically reducing minimum scan time. This reduction in scan time facilitates greater flexibility in acquisition, since the shortened scan time allowing for longer repetition times (to avoid metabolite saturation) and increased encoding matrix sizes. Comparison with a 1.5T 3D phase-encoded sequence showed that the flyback sequence can achieve comparable spatial resolution (7mm isotropic), improved spectral resolution, and significantly improved SNR in a 5-minute 3T exam as compared to a 17-minute scan at 1.5T.