High-Resolution Vessel Wall MRI in Ruptured Cranial Dural Arteriovenous Fistulas

Aims: High-resolution magnetic resonance vessel wall imaging (MR-VWI) is increasingly being used to characterize intracranial vascular diseases; specifically, we have demonstrated its utility in identifying the site of rupture in aneurysmal subarachnoid hemorrhage (SAH). Here, we report our preliminary experience in using MR-VWI to pinpoint the site of hemorrhage in ruptured intracranial dural arteriovenous fistulas (DAVFs).

Methods: A series of seven successive patients presenting to a single institution with ruptured cranial DAVFs underwent classical imaging including noncontrast computed tomography (CT), CT angiography, and digital subtraction angiography (DSA). Additionally, they also underwent high-resolution MR-VWI. Cross-section imaging was correlated with DSA and vascular substructures of each DAVF (i.e., venous varix, fistulas point, associated aneurysms) were evaluated for the presence of vessel wall enhancement and contiguity of hemorrhagic blood products.

Results: In four of seven patients presenting with ruptured DAVF, high-resolution MR-VWI sequences demonstrated a single focal point of robust vessel wall enhancement that was in immediate contiguity with hemorrhagic blood products. Notably, the vascular substructures demonstrating enhancement are known to be prone to hemorrhage (i.e., venous varix). In patients with multiple high-risk substructures (multiple venous varix and associated aneurysm), only a single structure demonstrated enhancement. In the remaining three patients presenting with ruptured DAVF without macrovascular substructures, high-resolution MR-VWI delineated the relationship between the blood product and the arterialized veins, but was insufficient to conclusively identify a site of rupture.

Conclusions: These cases extend our prior work using MR-VWI to identify the site of rupture in aneurysmal SAH to another intracranial vascular lesion, ruptured DAVFs. They provide proof of principle that the site of rupture in more complex intracranial vascular lesions can be identified by locating the portion of the DAVF that is both contiguous with the hematoma and demonstrates thick vessel wall enhancement. The accurate identification of the ruptured vascular substructure may inform clinical decision-making.