RADIOLOGICAL SOCIETY OF NORTH AMERICA 2003 (RSNA): Scientific Papers
Neuroradiology/Head and Neck (My Aching Back)

THE POTENTIAL VALUE FOR MRI IMAGING IN THE SEATED POSITION: A STUDY OF 63 PATIENTS SUFFERING FROM LOW BACK PAIN AND SCIATICA.

DATE: Thursday: December 04, 2004
START TIME: 11:00 AM
END TIME: 11:07 AM
LOCATION: ROOM N228
CODE: Q13-1312

PARTICIPANTS PRESENTER
Francis W. Smith, MD
University of Aberbeen, Scotland, U.K.

CO-AUTHOR: Malcolm Pope, PhD.

Keywords: Spine, MR

PURPOSE
With the availabilty of an MRI scanner capable of imaging in the erect postion and also open enough to allow for images of the lumbar spine to be obtained in flexion and extension, a study of 63 consequetive patients suffering from low back pain and sciatica referred for MRI examination was undertaken to assess what changes may be seen in different positions.

METHODS AND MATERIALS
Sixty three consecutive patients suffering from low back pain and/or sciatica, that had been referred for routine MRI examination, were studied. There were 20 female and 43 male patients aged 35 - 67 years of age (Mean 42 years). Each was exmined in a 0.6T Indominitable Stand-up MRI scanner (FONAR, Melville, New York). Sagital T1 and T2 images were made in the Supine and seated position. In the seated position the spine was imaged in neutral, flexed and extended. Transverse T2 weghted images were also made in neutral and in flexion. Each examination was evaluated by two trained observers.

RESULTS

In all of the cases there were at least one intervertebral disc which showed a loss of signal from the nucleus on the T2 images. There was no difference in disc height between supine and seated in the healthy discs. In those showing loss of signal from their nuclei there was a reduction in heightof between 1 - 3 mm. In 56 cases there was obvious prolapse of an intervertebral disc, whose degree of prolapse changed between the neutral position and either flexion or extension. In 6 cases there was anterior movement of disc and superior vertebra, on forward flexion demonstrating previously unsuspected spinal instability. In the other case an unsuspected position dependant spondylolisthesis showing associated tear of the interspinous ligament was found.

CONCLUSION
The ability of MRI images to be obtained in flexion and extension enables a diagnosis of spinal instability to be made with confidence. The alteration in disc height and appearance between the three positions is of great interest and requires further detailed study in a larger group of patients.