Gadolinium-DTPA--enhanced magnetic resonance imaging of a sequestered lumbar intervertebral disc and its correlation with pathologic findings.

A 37-year-old man developed spinal nerve root compression caused by a sequestered lumbar intervertebral disc that migrated caudally away from the L5-S1 interspace of origin. Magnetic resonance imaging (MRI) scans of the lumbosacral spine after administration of gadolinium-DTPA (Gd-DTPA) revealed intense peripheral, but not entire, enhancement of an extradural defect. The result of examination using Gd-DTPA-enhanced MRI increased the certainty of preoperative diagnosis of sequestered disc. Pathologic examination of the resected specimen showed that the extradural defect was sequestered disc material covered with vascularized granulation tissue, and indicated that the intense peripheral enhancement of the extradural defect in Gd-DTPA-enhanced MRI was related to the accumulation of contrast material within the vascularized granulation tissue surrounding the avascular sequestered disc material.