Diagnostic significance of CT discography

In a total of 179 patients, comprising 161 with intervertebral disorder and 18 with spondylolysis or spondylolisthesis, CT discographic findings of 456 intervertebral discs were reviewed. Computed tomographic discography showed the direction of herniation, the size of hernial masses, and the deformity of the intervertebral disc and joint, being helpful in deciding indications for surgery and selecting surgical procedures. Computed tomographic discographic patterns of disk deformity were classified as types A, B, and C. This classification almost concurred with the findings of conventional discography. Discography or CT discography is recommended to be used when deformity at the L5-S1 level may be missed on myelography and there is extraforaminal lateral disc herniation. Combined use of myelography, discography, and CT discography would increase the diagnostic accuracy for lumbar diseases. (Namekawa, K.)