Fig. 19.

Dural arteriovenous fistula. A 72-year-old male with progressive lower extremity weakness, without improvement in symptoms after lumbar laminectomy. a Axial T2 image demonstrates numerous flow voids in the thecal sac (arrowhead). There is high signal in the cord due to congestion (arrow). b There is long-segment high T2 signal in the cord, with serpiginous vessels in the posterior thecal sac (bracket). c Spinal angiogram shows the right T4–T5 supreme intercostal artery as a feeding vessel. d MRA confirms the arteriovenous connection