Contrast-enhanced, chemical shift MR imaging of the postoperative lumbar spine

Spin-echo MR imaging with intravenous enhancement has been very useful in evaluating the postoperative lumbar spine. Limitations, however, include difficulties in identifying subtle enhancement of scar and in distinguishing enhancement from epidural fat, which necessitates precontrast imaging. In this study, the authors have used a variant of the Chopper technique, based on frequency-selective excitation followed by in-phase and out-of-phase acquisitions. This sequence was used with intravenous Gd-DTPA in 10 patients who had undergone surgery for lumbar discogenic disease. MR imaging was performed at 1.5 T with both short repetition time, short echo time spin echo and Chopper before and after contrast material. In all cases, the regions of enhancement with intravenous contrast material were significantly more conspicuous, on Chopper sequences that on conventional spin-echo images. From their data, the authors believe that this type of chemical shift imaging, in combination with the use of intravenous contrast material, is useful in the evaluation of the postoperative lumbar spine