Imaging methods in examining the anatomy and function of the lumbar spine.

Conventional plain radiography, with or without flexion and extension images, is still the primary imaging modality of the lumbosacral spine despite the modern imaging methods. This is due to the simplicity of the technique and the good anatomical detail of the bone structure. Despite the limited information content of the plain radiographs, they are needed to serve as anatomical maps in connection with computed tomography or magnetic resonance imaging. In some institutions magnetic resonance imaging is now the primary modality for the evaluation of the lumbosacral spine, in others computed tomography and myelography still have a primary role, often depending on the availability of the devices. Magnetic resonance imaging clearly shows the anatomy of the discs, spinal nerves and dural sac. The diagnostic precision achieved with computed tomography in the evaluation of a herniated disc may also be achieved with magnetic resonance imaging. Differentiation of epidural scar from recurrent or residual disc herniation in patients with previous laminectomy, which with computed tomography myelography has been unreliable, can be evaluated by using magnetic resonance imaging enhanced with gadolinium-DTPA. The identification of facet joint disease is, however, less efficient with magnetic resonance imaging. Computed tomography and magnetic resonance imaging are probably nearly comparable in their accuracy in the evaluation of patients with sciatica. If cost and availability were not limiting factors, magnetic resonance imaging could provide an excellent screening technique for identifying individuals who would benefit from the identification of risks or preclinical disease or from institution of preventive measures.(ABSTRACT TRUNCATED AT 250 WORDS)