Spinal vascular malformations: MR angiography after treatment

PURPOSE: To evaluate the role of magnetic resonance (MR) angiography in the assessment of spinal vascular malformation therapy. MATERIALS AND METHODS: Thirty-four patients with spinal Vascular malformati ons (30 dural arteriovenous fistulas, two perimedullary arteriovenous fistu las, and two intramedullary arteriovenous malformations) underwent MR angio graphy and MR imaging before and after endovascular or surgical treatment. RESULTS: MR angiography showed residual flow in perimedullary vessels in se ven patients with dural fistula after embolization with liquid adhesive. In all seven, treatment failure was confirmed with arteriography. Long-lastin g disappearance of flow in perimedullary vessels was demonstrated at MR ang iography in 22 patients with dural fistula. MR imaging demonstrated normali zation of spinal cord volume in 16 of 22 patients and signal intensity on T 2-weighted images in three patients. Disappearance of cord enhancement was observed in five of 21 patients and of perimedullary enhanced vessels in si x of 13 patients. In one additional patient with dural fistula treated with embolization, early posttreatment MR angiography showed disappearance of f low in perimedullary vessels, which reappeared at follow-up and was consist ent with reopening of a small residual fistula. Posttreatment MR angiograph y demonstrated transient reduction of flow in the nidus in two patients wit h intramedullary malformations treated with embolization. Permanent disappe arance of flow in the perimedullary vessel was seen after endovascular trea tment in two patients with perimedullary fistula. CONCLUSION: MR angiography is more sensitive than MR imaging in depicting r esidual or recurrent flow in peri- or intramedullary vessels, which indicat es patency of the vascular malformation.