Fat-suppression contrast-enhanced MRI in the failed back surgery syndrome: a prospective study.

We examined 25 patients with recurrent pain after lumbar disk surgery with MRI to evaluate the usefulness of gadolinium (Gd)-enhanced fat-suppression (FS) imaging in patients with failed back surgery. Pulse sequences included T1-weighted (T1W) images, Gd-enhanced T1W images, and Gd-enhanced T1W images with FS. The addition of FS to Gd-enhanced T1W images improved visualization of enhancing scar in all cases, helped distinguish scar from recurrent herniated disk, and showed more clearly the relationship of scar to the nerve roots and thecal sac. The images also demonstrated enhancement of the facet joints and theca in 23 and 11 cases, respectively. Intradural nerve roots were more conspicuous with FS in 21 cases. The combination of unenhanced and Gd-enhanced T1W images with FS is recommended for routine examination of the postoperative back.