| Part 1 The application of magnetic resonance angiography in spinal dural arteriovenous fistulas Object: The purpose of this study was to evaluate the accuracy of contrast-enhanced magnetic resonance angiography(CEMRA) in demonstrating spinal dural arteriovenous fistulas(SDAVFs). Methods: The authors studied 15 patients with SDAVFs(11 men, 4 woman; age range, 38–81 years; mean, 60 years), including 1 with spinal epidural AVFs, who underwent preoperative dynamic contrast-enhanced MRA at 3T and digital subtraction angiography(DSA). In the evaluation CEMRA images, inspection was focused on the presence of the following findings: dilated perimedullary veins in the spinal canal; focal enhancement of the nerve root, suggesting the location of the AVF, around the dural sleeve; and the level of the artery feeding the spinal dural arteriovenous fistula on the basis of continuity between the feeder and abnormal spinal vessels. The utility of CEMRA was assessed by comparing these findings with those of DSA in each case. Results: On DSA, the vessel feeding the spinal dural arteriovenous fistula was the intercostal artery(8cases), the lumbar artery(5cases), and the internal iliac artery or the ascending pharyngeal artery(1 case each), and CEMRA detected dilated perimedullary veins in all 12 patients. In 8 patients, there was focal enhancement of the nerve root. The radicular vein that drains the AVF into the perimedullary veins was found in 8 cases. In 4 of 7 cases who underwent both preoperative CEMRA and DSA, the CEMRA-derived level and site of the AVF and its feeder corresponded with those shown by DSA. In 3 patients, however, the CEMRA-derived locations of the fistulas were not consistent with that which were confirmed by DSA. In 1 case, CEMRA could not detect the multiplicity of their feeders. CEMRA can visualize and localize the level of the AKA(Adamkiewicz artery) correctly in 11 of 12 cases(91%). Intermodality agreement with DSA for fistulas level was good for 3T CEMRA(57.1%). Conclusions: For the localization of spinal dural arteriovenous fistulas, CEMRA may be a reliable tool. Meanwhile, the use of CEMRA preceding DSA can be helpful to focus the selective catheter angiography on certain spinal levels, and image quality of CE-MRA is sufficient for detection of the AKA. CEMRA is a useful non-invasive examination for the detection and localization of SDAVF. CEMRA facilitates but does not replace DSA as confirmation of location, fistula type, and arterial detail, which are required before treatment. Further study in a larger population is warranted to assess the accuracy of this technique.Part 2 Spinal arteriovenous fistulas:clinical analysis in 15 patients Objective: Among the all spinal vascular malformations, the spinal arteriovenous fistulas(SDAVF) is the most common subtype. Fistulas are located intradurally at the sleeve of the nerve root. The arterial blood from the meningeal branch of the segmental artery flows through the fistula which then drains through the arterialized vein into the coronal venous plexus. The increased venous pressure of the arterialized vein leads to diminished draining of the normal spinal veins, and venous congestion accompanied with intramedullary edema occurs. To evaluate the clinical outcome of patients with spinal arteriovenous fistulas who underwent surgery,and discuss the modality of SDAVF. Methods: Fifteen patients were hospitalized for spinal arteriovenous fistulas in our department from December 2011 to November 2014.All patients underwent MRI and DSA examinations to axial and sagittal plane of spinal before operation. Surgical interruption of arterialized radicular-medullary draining vein of SDAVF provides permanent occlusion of the fistula. Results: Improvement occurred in 13 cases. Conclusions: Surgery obliteration of SDAVF is an effective and safe procedure. After successful surgical obliteration, motor symptoms improve in the most patients. |
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