Diskography is a diagnostic procedure used to determine whether or not the disc is a source of axial neck or back pain. The procedure is performed with the assistance of fluoroscopy to guide needle placement and to visualize the distribution of dye in the disc. Water soluble dye is injected into the discs, while careful attention is paid to the pressure of the injection. If this injection causes the usual pain at a level of 7/10 on pain scale in the usual location at less than 50 PSI pressure, this identifies this particular disc as being the pain generator. This should also correlate with results of a CT scan obtained immediately after the discography. The CT should show grade III or higher internal disc disruption in the same disc to positively identify discogenic pain.