Peripheral spinal cord hypointensity on T2-weighted MR images: A reliable imaging sign of venous hypertensive myelopathy

BACKGROUND AND PURPOSE: MR findings reported in conjunction with spinal dur al arteriovenous fistula (SDAVF) include cord swelling, increased T2 signal within the spinal cord, and parenchymal enhancement, each of which is nons pecific. Enlarged vessels on the cord surface, the most specific MR finding , is noted in only half of SDAVF patients. Nevertheless, we have frequently observed MR peripheral hypointensity of the spinal cord in SDAVF on T2-wei ghted images, which is not characteristic of nonvascular or nonhemorrhagic causes of myelopathy and which has not been described in association with S DAVF. We hypothesized that peripheral cord hypointensity might reliably sug gest the diagnosis of SDAVF or other causes of venous hypertensive myelopat hy. METHODS: We reviewed the MR findings in 11 consecutive cases of angiographi cally confirmed symptomatic SDAVF and in four cases of intracranial dural a rteriovenous fistula with spinal drainage, a lesion that also causes spinal cord deficits mediated by venous hypertensive myelopathy. RESULTS: In each case, T2 hypointensity involving the cord periphery was pr esent. This sign has not been previously described in association with eith er SDAVF or other causes of venous hypertensive myelopathy. It appears, how ever, to be a relatively constant imaging feature of SDAVF. CONCLUSION: If the absence of spinal hemorrhage, T2 hypointensity involving periphery of the spinal cord suggests venous hypertensive myelopathy as a cause of spinal cord dysfunction.