The diagnosis of herniated intervertebral disks with MR imaging: a comparison of gradient-refocused-echo and spin-echo pulse sequences.

Axial MR images of 65 lumbar disks with herniated nucleus pulposus imaged by gradient-refocused-echo (GRE) and spin-echo (SE) MR pulse sequences of 200-400/15 with a flip angle of 15-30 degrees was selected as optimal because of its high signal-to-noise ratio and good contrast between CSF, nucleus pulposus, and bone. The GRE technique was confirmed to be more sensitive in detecting prolapsed disks than the SE technique, but was less sensitive in demonstrating extruded disks. The combination of axial GRE and SE resulted in high detectability of herniated nucleus pulposus on axial MR images. Our results suggest that the GRE technique is an important adjunct to SE imaging in studying herniated nucleus pulposus.