Brian S. Kim MD, Presenter: Nothing to Disclose

Harpreet S. Dhatt BS, Abstract Co-Author: Nothing to Disclose

Erik Supratik Mittra MD, PhD, Abstract Co-Author: Nothing to Disclose

Bao H. Do MD, Abstract Co-Author: Nothing to Disclose

Edward E. Graves PhD, Abstract Co-Author: Nothing to Disclose

Sandip Biswal MD, Abstract Co-Author: Nothing to Disclose

Understanding spinal cord and cauda equina glucose metabolism may provide insight into causes or manifestations of low back pain. We have retrospectively characterized the distribution of 2-deoxy-2-[18F]-fluoro-D-glucose (18F-FDG) within the entire length of the spinal canal in subjects with and without low back pain using whole body PET/CT.

Approval of the study was attained by our IRB. A retrospective review of 14 negative whole body 18F-FDG PET/CT studies with non-CNS cancers was performed. Seven of the subjects had described ‘low back pain’ (LBP) and the remaining 7 subjects (control) described ‘no pain’ on their entrance questionnaire. Studies with vertebral marrow hyperplasia, severe spinal arthritis, cervical/thoracic kyphosis or motion artifact had been previously excluded. Using the transaxial CT to define the spinal canal, oval region of interests (ROIs) of fixed dimensions were placed within the canal and excluded the bony elements of the spine. Using this ROI, corresponding PET measurements were obtained at every slice of the study from C1 to S1. ROI measurements included average standard uptake values (SUVavg). Transaxial measurements at L5, where minimal neural tissue is present, served as an internal control. For each vertebral level, mean SUVavg was calculated. For comparative analysis, we defined the canal-to-background (CTBavg) ratio as canal mean SUVavg:L5 SUVavg. Data was analyzed using RT Image analysis software and two-tailed Student t-tests. Significance is p<0.05.

The mean L5 SUVavg was 0.75 and 0.82 for LBP and control patients which was not statistically different (p<0.38). Significantly higher mean CTBavg values were observed at vertebral levels T8, T9 and T10 in LBP subjects over controls (1.66, 1.73 and 1.78 versus 1.39, 1.37 and 1.44; p<0.033, 0.020 and 0.048, respectively).

Increased 18F-FDG uptake is observed in the distal thoracic spinal canal in subjects describing low back pain. Increased neurosensory and neuromotor activity in the spinal cord at these levels related to LBP may explain this observation.

18F-FDG PET/CT can potentially objectify spinal cord activity related to nociception.

Kim, B, Dhatt, H, Mittra, E, Do, B, Graves, E, Biswal, S, A Difference in the Pattern of 18F-FDG Uptake Is Observed within the Spinal Canal in Low Back Pain Patients.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5016475.html