We analyzed fifteen cases which showed spontaneous regression of lumbar disc herniation on MR imaging. Their characteristic clinical pictures were as follows; patients complained of acute onset of severe leg pain, the pain decreased within several weeks, but numbness and/or muscle weakness remained in some cases. Types of herniation were sequestration in 7 cases, extrusion in 8 cases. Gd-DTPA enhanced MRI were performed in 12 cases, and eleven of them showed the finding of a “wrapped disc” that was enhanced around the herniated mass. The herniated mass demonstrated high intensity on T2 weighted images in the course of spontaneous regression.
