Spinal dural arteriovenous fistulas: recognizing the spectrum of magnetic resonance imaging findings.

Spinal dural arteriovenous fistulas are the most common type of vascular malformation to involve the spinal cord. In this report, we describe and analyze the various magnetic resonance imaging (MRI) findings of spinal dural arteriovenous fistulas in order to increase awareness and prompt timely diagnosis. We reviewed 14 patients evaluated and treated for spinal dural arteriovenous fistulas over a seven year period, with special attention to findings on MRI. All patients had regions of increased cord signal on T2-weighted MRI, with corresponding hypointense signal on T1-weighted images in 11 patients (79 percent). Thirteen (93 percent) of 14 patients had focal increased cord caliber and eight (57 percent) had prominent intradural vessels. Cord enhancement was observed in all seven patients who were administered contrast and two patients had enhancement of intradural vessels. These imaging findings are relatively nonspecific, but should lead to further investigation with myelography or arteriography in the appropriate clinical setting.