Applications of diffusion weighted imaging in detection of radiating pain to lower extremities

To examine the hypothesis that diffusion weighted imaging (DWI) in lumbosacral region could reveal sciatic nerve course swelling that lead to lower extremity pain. The aim of present article was to find and evaluate the diffusion weighted coefficients (b-values) for scrutinizing sciatic nerve tract changes in lumbosacral region.

Lumbar area was imaged in 30 patients with lower extremity pain in one side (left or right) at 1.5 T MR with routine protocols and DWI. Two stages for processing images were generated. Distance of sciatic nerve fibers between all patients In terms of Gray level average (GLA) and Contrast average (CA) on each side were calculated by MATLAB software. An appropriate statistical test such as Paired T test was used and. P<0.05 was considered as significant

In the first stage of image processing there was no significant result in affected side rather than normal side. In the second stage, the mean b-value was significantly correlated with affected side that represent nerve swelling and the mean ADC was positively related to affected side. In b-value images, the diameter of affected side is greater than the healthy side and P<0.001 showed significant results. The CA of affected side is greater than healthy side and P<0.001 illustrated significant results. For GLA, statistics showed the greater values for affected side in comparison to healthy side and P<0.001 was significant.

Based on the results of present study, neurography is possible way to visualize early changes, such as nerve indentation and swelling, and to qualitatively evaluate affected lumbar nerves course in patients with lower extremity pains.