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| T1 pre-gad | T2 FSE | L T11 angiogram |
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| T1 pre-gad | T2 FSE | L T11 angiogram |
Type I AVM is really a dural AV fistula and is most commonly seen in the lower thoracic cord or conus. They are the most common type of AVM and are usually seen in men over the age of 50. Many are spontaneous however 40% are thought to be due to trauma. The fistula itself is not visible on MR; however, the dilated draining veins are often apparent with abnormal increased signal within the cord on T2.
Type II AVMs are intramedullary lesions, and are also known as glomus malformations. They present in younger patients than dural AVMs and are usually seen in the dorsal aspect of the cord, often at the cervicomedullary junction. Feeding vessels may arise from the anterior or posterior spinal arteries. Intramedullary cord hemorrhage is a complication.
Type III AVMs are also known as juvenile AVMs. They are vascular masses which involve the cord and have an extra-spinal component as well.
Type IV spinal AVMs (perimedullary) are intradural/extramedullary lesions usually near the conus presenting in younger adulthood with myelopathy secondary to cord ischemia caused by venous congestion. Most have feeders from the anterior spinal artery and are ventral to the cord as in this case. Related Cases
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| Type II spinal AVM | Type IV spinal AVM |