We performed serial MRIs after Gd-DTPA injection in 30 patients with lumbar disc herniation, and their findings were classified into the following 3 groups. Group A: no enhancement, Group B: partial enhancement, Group C: circulatory enhancement (socalled wrap-around disc). Axial area of the herniated mass in MRI and pain of the lower limbs were continuously evaluated. Decrease in lower limb pain correlated closely with reduction in the herniated mass. Regression of the herniated mass in group C occurred within two or three months, and leg pain in group C was reduced by half within two months.
On the other hand, in patients with a large central herniation, reduction of the herniated mass and decrease in leg pain were hardly recognized. It is considered that enhanced MRI is useful for predicting the natural history of the lumbar herniated disc.