[MRI of the intervertebral disk]

Failure to respond to conservative treatment and recurrent disease after operative intervention are the major indications for diagnostic imaging in degenerative disc disease. In recent years computed tomography (CT) has widely replaced myelography, and now CT is giving way to magnetic resonance imaging (MRI). MRI yields diagnostic information comparable to that obtained with myelo-CT, yet spares the patient the need for intrathecal contrast administration or exposure to ionizing radiation. In the postoperative spine, contrast-enhanced MRI has proven more accurate than CT in distinguishing epidural scar formation from recurrent disk herniation.