CT attenuation numbers in the lumbar spine and their utility in diagnosing disc disease

Normal CT attenuation values for various structures in the lumbar spine were obtained on several CT scanners. The wide range of normal makes using absolute CT numbers unreliable. The utility and pitfalls of using CT attenuation numbers in the lumbar spine are discussed and several examples are illustrated. CT numbers used as absolute values can be misleading, whereas, when used as relative values for comparison with other structures, they can be quite valuable.