Post-operative lumbar spine: comparative study of TSE T2 and turbo-FLAIR sequences vs contrast-enhanced SE T1.

AIM

To compare turbo T2 weighted spin echo (TSE T2) and turbo-FLAIR (fluid attenuated inversion recovery) vs gadolinium enhanced T1 weighted spin echo (SE T1) sequence in the differential diagnosis between disc herniation and post-surgical fibrosis.

MATERIALS AND METHODS

Sixty-four patients who underwent surgical treatment for lumbar disc herniation with persistent or recurrent post-surgical symptoms were studied with a 0.5 Tesla MR system. The sequences used were TSE T2, turbo-FLAIR and T1 SE with and without intravenous gadolinium DTPA. The enhanced T1 SE sequence was considered the gold standard. Sensitivity and specificity were calculated.

RESULTS

The sensitivity was 100% for both TSE T2 and turbo-FLAIR sequences. The specificity was 94% for TSE T2 and 92% for turbo-FLAIR. Negative predictive value was 100% for both sequences and positive predictive value 84% and 80% for TSE T2 and turbo-FLAIR, respectively.

CONCLUSION

Although both sequences show high sensitivity, TSE-T2 presents greater specificity than turbo-FLAIR as compared to enhanced T1 SE. TSE T2 also offers the advantage of myelographic effect. We consider that the use of rapid sequences may avoid the need for intravenous contrast medium in most cases, reserving gadolinium DTPA only to those where all the criteria for hernia or fibrosis are not fulfilled.