Magnetic resonance imaging of lumbar spinal disorders

To evaluate the stenotic condition of the lumbar spinal canal, MRI was compared with myelography and with discography in 102 patients, all of whom underwent surgical exploration. Various pathologic conditions were studied including 50 cases of herniated nucleus pulposus, 39 cases of lumbar canal stenosis (central, peripheral type or combined type), and 13 cases of spondylolisthesis (degenerative, spondylolytic, and dysplastic type). High correlation was detected between the T2 weighted mid-sagittal image of the thecal sac and the lateral view of a full-column myelogram, but subtle changes such as adhesive changes, or redundancy, or anomalous changes of the nerve roots were more clearly demonstrated on myelograms than on MRI. Actually some of these changes could not be detected on MRI. The degrees of disc degeneration were classified into five grades according to the signal intensity and the irregularity of the disc on the T2-weighted image. The MRI evaluation of disc degeneration in this series was similar to that of the discography. However, MRI could not replace discography for identifying the source of pain in symptomatic patients. Although MRI might be the imaging modality for diagnostic screening and for detecting stenotic conditions of the lumbar spinal canal, it will not be able to replace myelography and/or discography for determining indication for surgery and preferred surgical approach. (author)