Dural arteriovenous fistula at the craniocervical junction with perimedullary venous drainage.

MR imaging showed swelling and diffuse signal changes in the spinal cord in two patients with progressive myelopathy. MR angiography revealed slow-flow perimedullary vessels extending to the skull base, which are consistent with drainage vessels of a dural arteriovenous fistula at the craniocervical junction. This fistula was subsequently seen in both patients on selective arteriograms of the ascending pharyngeal and vertebral arteries.