A prospective comparison of computed tomography and myelography in the diagnosis of herniated lumbar disks.

Although CT effectively demonstrates normal and herniated intervertebral disks, the value of CT in low back pain has not been adequately evaluated. We compared CT prospectively with myelography in 107 patients referred to Ulleval Hospital Department of Radiology for myelography. Fifty-two patients subsequently had spinal explorations, one patient twice during the study and two patients at two levels. Forty-six CT and 44 myelographic diagnoses agreed perfectly with the operative diagnosis at that level. In 30 disk herniations, there were 29 true-positive CT diagnosis and 28 true-positive myelographic diagnoses. False-negative diagnoses of herniated nucleus pulposus were made twice on myelography and once on CT. In 24 other spinal operations, there were eight false-positive CT and nine false-positive myelographic diagnoses of herniated nucleus pulposus. CT demonstrates lumbar disk disease as effectively as myelography.