GRASE (gradient- and spin-echo) MR of the brain

To assess the clinical utility of GRASE (gradient- and spin-echo) MR imaging of the brain by comparing it with the T2-weighted turbo spin-echo technique.

Fifty-three consecutive patients referred for MR imaging of the brain were studied with T2-weighted turbo spin-echo and GRASE techniques, matched for effective echo time (110 milliseconds), echo train length (eight), and spatial resolution. The examinations were evaluated independently by two neuroradiologists for lesion detection (high- and low-signal-intensity lesions) and lesion conspicuity, and for susceptibility, motion, and chemical-shift artifacts.

The GRASE technique provided greater detection of both high- and low-signal-intensity lesions and of low-signal-intensity lesions with paramagnetic susceptibility characteristics (ie, calcium and hemorrhage). Chemical-shift artifacts in the frequency-encoding direction were more prominent with the turbo spin-echo technique, whereas chemical-shift artifacts in the phase-encoding direction were more prominent with the GRASE technique. There was no significant difference in the degree of diamagnetic susceptibility artifacts at the base of the skull, or in motion artifacts.

T2-weighted GRASE is a fast imaging technique with a potential for replacing turbo spin-echo in routine MR imaging of the brain. GRASE maintains the contrast resolution of turbo spin-echo imaging and is better at depicting lesions with paramagnetic susceptibility characteristics.