The value of MR neurography for evaluating extraspinal neuropathic leg pain: A pictorial essay

Fifteen patients with neuropathic leg pain referable to the lumbosacral ple xus or sciatic nerve underwent high-resolution MR neurography. Thirteen of the patients also underwent routine MR imaging of the lumbar segments of th e spinal cord before undergoing MR neurography. Using phased-array surface coils, we performed MR neurography with T1-weighted spin-echo and fat-satur ated T2-weighted fast spin-echo or fast spin-echo inversion recovery sequen ces, which included coronal, oblique sagittal, and/or axial views. The lumb osacral plexus and/or sciatic nerve were identified using anatomic location , fascicular morphology, and signal intensity as discriminatory criteria, N one of the routine MR imaging studies of the lumbar segments of the spinal cord established the cause of the reported symptoms. Conversely, MR neurogr aphy showed a causal abnormality accounting for the clinical findings in al l 15 eases. Detected anatomic abnormalities included fibrous entrapment, mu scular entrapment, vascular compression, posttraumatic injury, ischemic neu ropathy neoplastic infiltration, granulomatous infiltration, neural sheath tumor, postradiation scar tissue, and hypertrophic neuropathy.