MRT was performed, using a 0.5 and 1.5 Tesla magnet, on 150 patients with FBSS between three days and 23 years following lumbar disc surgery. T1-weighted spin echo sequences were obtained before and after the application of gadolinium (0.15 mmol/kg). In 67 patients the MRT findings were compared with surgical observations. MRT had a sensitivity of 94% in diagnosing recurrent prolapse, a specificity of 100% and accuracy of 94%. The ventral epidural scar tissue, the disc and the neighbouring vertebral bodies showed increased contrast uptake over a prolonged post-operative period.