Imaging description

Spinal vascular malformations (SVMs) are a rare and heterogeneous group of entities with various subsets that present with differing clinical and imaging appearances. There are multiple proposed classifications and there is considerable overlap in entities within the reported literature. Two of the most commonly encountered SVMs, dural arteriovenous fistulas (DAVF) and spinal cord arteriovenous malformations (AVM), constitute a large majority of these lesions.

DAVFs are acquired shunts that are located within the dura, most commonly in the nerve root sheath. It is supplied by the meningeal branch of a radicular artery and the drainage is into a dilated vein coursing intradurally and eventually into perimedullary venous plexus (Fig. 100.1). The imaging manifestations are simply a result of dilated perimedullary veins, venous hypertension, and its effect on the spinal cord. Enlarged venous structures can result in perimedullary flow voids that are best demonstrated on T2-weighted sequences (Fig. 100.2). Long-standing venous hypertension can result in cord edema and expansion. There may be faint enhancement of the cord on contrast administration. The perimedullary venous system may also demonstrate enhancement after contrast administration (Fig. 100.3).