GADOLINIUM-DTPA ENHANCEMENT OF SYMPTOMATIC NERVE ROOTS IN MRI OF THE LUMBAR SPINE

Disc prolapse presenting with sciatica may be associated with enhancem ent of the symptomatic nerve root following magnetic resonance imaging (MRI) with intravenous gadolinium (Gd)-DTPA. Previous studies have sh own, however, that this does riot occur in all cases. The aim of this study was to assess the incidence of nerve root enhancement in patient s with sciatica and disc prolapse and to try to identify any specific features:that:might be associated with the phenomenon. A total of 227 patients presenting with low back pain and/or sciatica underwent a MRI study of the lumbar spine with intravenous contrast enhancement. Nine teen of 81 (23.5 %) patients with disc prolapse demonstrated nerve roo t enhancement. Nerve root enhancement had a highly significant associa tion with sequestrated disc lesions (13/19, 68 %; P < 0.0005), and was primarily seen in the symptomatic ipsilateral nerve root (16/19, 84 % ). The sensitivity of nerve root enhancement associated with disc prol apse was 23.5 % with a specificity of 95.9 %, a positive predictive va lue of 76 % and a negative predictive value of 69.3 %. Nerve root enha nce may be indicative of the symptomatic level but its poor sensitivit y negates the routine use of Gd-DTPA in MRI for sciatica.