A discogram, or diskogram, is a test used to evaluate back pain. A discogram may help your doctor determine if your back pain could be caused by an abnormal disk in your spine. Spinal disks look a little like jelly doughnuts, with a tough outer layer and a gel-like substance inside. Disks act as cushions between the vertebrae in your spine.
During a discogram, dye is injected into the soft center of the disk. The injection itself sometimes reproduces your back pain. Several disks may be injected, to try to pinpoint the cause of your back pain. In addition, the dye will move into any cracks in the disk's exterior and will show up on an X-ray or CT scan.