A discogram, or diskogram, is a test used to evaluate back pain. A discogram may help your doctor determine if an abnormal disk in your spine is causing your back pain.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 bones 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.The dye also moves into any cracks in the disk's exterior, which can then be seen on an X-ray or CT scan. However, disks that show signs of wear and tear don't always cause symptoms, so the usefulness of a discogram is controversial.