Functional MRI of the lumbar spine in erect position in a superconducting open-configuration MR system: Preliminary results

The purpose of this study was to determine the feasibility of obtaining, an d findings in, functional MRI of the lumbar spine in an erect position and with flexion and extension. Thirty subjects (including 5 volunteers) were i maged in a sitting position and while performing flexion and extension, The alternations in posterior disk margin, size of neural foramina, and centra l canal were evaluated. In addition, routine supine imaging was accomplishe d in 15 of these subjects. The foraminal size and posterior disk margins di d not change appreciably from supine to upright position, With extension, t here was an increased disk bulge in 27% of disks (40% of those with desicca tion). Central canal size (50%) and foraminal size (27%) decreased with ext ension, especially at levels with disk desiccation. Images obtained with ou r open-configuration MR unit were diagnostically adequate, although of infe rior quality compared with those obtained with a conventional unit. Our pre liminary results show the feasibility of obtain ing diagnostic images of th e erect lumbar spine with flexion and extension. The results are in agreeme nt with those obtained with cadaveric studies. The utility of this method i n diagnostic imaging of patients with low back pain remains to be determine d.