Transverse axial tomography of the spine.

Transerse axial tomography is a technique by which the spine is viewed radiographically in cross section. The tomographic apparatus, technique of examination, and radiation exposure will be discussed. Examples of normal and pathologic anatomy of the cervical, thoracic, and lumbar spine will be presented. In the lumbar spine cross-sectional views of stenotic canals due to facetal hypertrophy, congenital stenosis, spondylolithesis, and ventral overgrowth of spine fusions will be demonstrated. Measurements of the sagittal and interpedicular distances on conventional x-rays have correlated poorly with the anatomic state in lumbar stenosis. A high degree of correlation has been demonstrated by plotting the cross-sectional area configuration of the bony canal, as well as a new measurement, the interfacet distance, on axial tomograms. Transverse axial tomography is an exciting, new approach in neuroradiology for the evaluation of spinal disorders which have primarily axial distortion.