SPINAL DURAL ARTERIOVENOUS-FISTULAS - EVALUATION WITH MR-ANGIOGRAPHY

PURPOSE: To show that postgadolinium three-dimensional time-of-flight MR angiography shows abnormal intradural vessels associated with spina l dural arteriovenous fistula better than routine MR imaging and provi des screening information useful for subsequent diagnostic conventiona l angiography and/or posttreatment evaluation. METHODS: Precontrast an d postcontrast MR imaging and MR angiograms, as well as subsequent dig ital subtraction angiograms, were obtained for eight patients with dur al arteriorvenous fistulas, diagnosed with digital subtraction angiogr aphy and verified with surgery. In four patients, MR studies also were obtained after surgery. RESULTS: All patients had cord hyperintensity of T2-weighted images and postgadolinium enhancement on T1-weighted i mages. Five had vessellike signal abnormalities in the subarachnoid sp ace on MR. Abnormal intradural vessels were detected in all eight pati ents with MR angiography. Comparison with digital subtraction angiogra phy revealed these vessels to be primarily enlarged veins of the coron al venous plexus on the cord surface. In six patients, the medullary v ein draining the fistula was demonstrated, indicating the level of the fistula, later identified by digital subtraction angiography. After s urgical obliteration of the fistula, the draining medullary vein and m ost or all of the abnormal coronal veins were no longer demonstrated, with decrease or resolution of cord hyperintensity on T2-weighted imag es. CONCLUSION: Postgadolinium, spinal MR angiography in cases of susp ected dural arteriovenous fistula provides information about intradura l veins that supplements the diagnostic value of the MR imaging result s, facilitates the subsequent digital subtraction angiography study, a nd, in treated cases, reflects the success of surgery and/or embolizat ion.