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The authors performed a retrospective review of postmyelographic CT scans from 49 consecutive patients seen between January 2009 and August 2018 with imaging and/or clinical findings related to intracranial hypotension. Each scan was evaluated by both a neuroradiology fellow and a board-certified neuroradiologist for the presence of contrast in the renal excretory system. A similar assessment was also performed on 90 consecutive control subjects who underwent CT myelography for alternative indications. Among the 49 patients with suspected CSF leak, 21 (43%) had an overt CSF leak on postmyelographic CT (group 1) and 28 (57%) did not (group 2). Overall, renal contrast was identified in 7/49 patients (14.3%): 5 (24%) patients in group 1, and 2 (7%) patients in group 2. Renal contrast was not seen in any of the 90 controls on postmyelographic CT. Renal contrast was exclusively seen in patients with a clinically or radiographically suspected CSF leak. Identification of this finding should prompt a second look for subtle myelographic contrast extravasation or an underlying CSF-venous fistula.

Spinal dural arteriovenous fistulas (sdAVFs) usually become symptomatic in elderly men, who are affected 5 times more often than women. Symptoms caused by sdAVF comprise gait disturbances with or without paresis, sensory disturbances in the lower extremities, pain, and sphincter and erectile dysfunction. The authors retrospectively analyzed their medical data base for all patients treated for spinal dural arteriovenous fistula at their institution between 2006 and 2016. Patient age, neurologic status at the time of diagnosis, the duration of symptoms from onset to diagnosis, and follow-up information were evaluated. The extent of medullary T2WI hyperintensity, intramedullary contrast enhancement, and elongation of perimedullary veins on MR imaging at the time of diagnosis were additionally analyzed. Data for long-term outcome analysis were available in 40 patients with a mean follow-up of 52 months. The mean age at the time of diagnosis was 69 years (median, 71 years; range, 53-84 years) with a male predominance (80%). The mean duration of symptoms was 20 months. Spinal dural arteriovenous fistulas are characterized by inter-individually variable clinical presentations, which make a determination of specific predictors for long-term outcome more difficult. Fast and sufficient diagnosis might result in a better outcome after treatment. The diagnosis of spinal dural arteriovenous fistula remains markedly delayed, reflecting an ongoing lack of knowledge and awareness among treating physicians of this rare-but-serious disease.