CT diagnosis of degenerative disc disease. The bulging annulus.

Computed tomography can accurately distinguish a bulging disc with intact annulus from a herniated nucleus pulposus in most patients. A bulging annulus should be diagnosed when CT scans demonstrate generalized extention of the disc margins beyond the adjacent vertebral body margins. A herniated nucleus may be diagnosed by a CT scan when there is focal protrusion of the disc margin beyond the vertebral body margins. However, correlation between clinical and CT findings remains a critical factor in determining the significance of an abnormality detected by a CT scan.