ABSTRACT
For evaluating the lumbar disc space, the fact that the postmyelography computed tomography was more accurate than computed tomography or myelography is well-known. But the technical difficulty is limitation of gantry angle. The prone position scanning may help to lessen this trouble. A prospective computed tomographic scanning was performed in both the prone and supine position on 43 patients, who had low back pain. The angle between the vertebral end plate and vertical line was measured in both position at L3-4, L4-5 and L5-S1 interspaces. The advantages of prone scanning in spinal aligment was noted at L5-S1 disc space(79.1%) and also more desirable if computed tomography was performed with metrizamide. With above advantages, the evaluation of bulging annulus was became more easier.