MEASUREMENT OF LUMBAR SPINE FLEXION-EXTENSION USING A LOW-FIELD OPEN-MAGNET MAGNETIC-RESONANCE SCANNER

RATIONALE AND OBJECTIVES. The authors investigated the feasibility of using a low-field open-magnet magnetic resonance (MR) scanner to acqui re functional flexion-extension images for range of motion (ROM) measu rements on the lumbar spine, METHODS. Seventeen healthy subjects with no symptoms of back pain (age range, 22-59 years) were scanned in a lo w-field open-magnet MR scanner in the flexed, neutral, and extended po sitions, Each image was downloaded to a computer workstation for subse quent flexion-extension, lordosis, and ROM measurement, RESULTS. Data from two subjects were not analyzed because their images did not show all the lumbar vertebrae. For the remaining 15, there was a large vari ation in the magnitude of the ROM values (range, 9 degrees-70 degrees; mean 36.4 degrees, SD 16.5 degrees), However, there was a significant correlation between age and ROM (r = -0.63; P < 0.05), CONCLUSIONS. T he low-field open-magnet MR scanner provides a method for noninvasive imaging of the lumbar spine, allowing the subject freedom of movement in the horizontal plane. This enables functional flexion-extension ima ges of the lumbar spine to be acquired.