Magnetic resonance imaging of the weight-bearing spine.

Weight-bearing magnetic resonance (MR) imaging of the spine can either be simulated by imaging the patient in the supine position in combination with a special axial loading device or be achieved by using vertically open-configuration MR systems, which allow for in vivo MR images of the spine under upright weight-bearing conditions in either seated or standing body positions. Weight-bearing MRI of the spine permits the study of physiological as well as pathological changes in the relationships of the intervertebral disk, the spinal canal, and the neural foramina as well as the assessment of segmental instability in physiologic body positions. With this technique, MR images may be taken in painful body positions so that morphological changes of the intervertebral disk or other spinal structures may be correlated with pain or other symptoms. In selected cases, weight-bearing MRI of the spine may demonstrate clinically relevant neural compromise or foraminal stenosis, which may be occult on conventional MR images obtained in the supine position.