MAGNETIC-RESONANCE-IMAGING OF THE BRAIN WITH GADOPENTETATE DIMEGLUMINE-DTPA - COMPARISON OF T1-WEIGHTED SPIN-ECHO AND 3D GRADIENT-ECHO SEQUENCES

TR, short TE, high resolution, 3D gradient-recalled echo (GRE) imaging was evaluated for lesion detection in the brain, High resolution 3D G RE data acquisition was used to reduce partial volume effects and now artifacts, to better visualize smaller structures, to minimize signal losses caused by held inhomogeneities, and to allow better image refor matting. Spin-echo (SE) and 3D GRE approaches were compared for lesion detection after the administration of an MR contrast agent, gadopente tate dimeglumine. Preliminary clinical studies demonstrated that the s ignal-to-noise ratio (SNR) in each slice of the GRE scan was worse tha n that of the SE scan because of the much thicker slices acquired with the SE technique, However, by averaging two adjacent 3D slices, the S NR of the two methods was essentially equivalent, In the averaged GRE slices, large lesions were seen just as well as in the SE images, More importantly, small lesions were better visualized in the thin 3D GRE images than in the thick SE images for the lesions studied in this wor k and the protocols used. These observations were confirmed by theoret ical simulations.