Purpose:
High-resolution magnetic resonance vessel wall imaging (MR-VWI) is increasingly being used to characterize intracranial vascular diseases.  Recent studies support a paradigm of avid vessel wall enhancement in ruptured or unstable (but not stable, unruptured) intracranial aneurysms.  Here we report our preliminary experience in using MR-VWI in the evaluation of ruptured cranial dural arteriovenous fistulas (dAVFs).

Methods:
A retrospective review of a prospective intracranial MR-VWI database identified a consecutive series of patients with ruptured cranial dAVFs. All patients underwent standard imaging including non-contrast CT, CT angiography, and digital subtraction angiography (DSA). High-risk angio-architectural features, e.g., venous-side aneurysms and varices, were identified and a site-of-rupture determined, if possible, using traditional criteria. MR-VWI was used to evaluate high-risk angio-architectural features for (1) robust enhancement and (2) contiguity to hemorrhagic blood products.

Results:
Four of seven patients with ruptured cranial dAVFs demonstrated at least one high-risk angio-architectural feature on classical imaging thought to be the site-of-rupture. In all cases, this arterialized venous structure demonstrated robust vessel wall enhancement and was located immediately adjacent to hemorrhagic blood products on MR-VWI. In patients with multiple, high-risk angio-architectural features, only the feature in contiguity with blood and thought to be the site-of-rupture demonstrated enhancement.

Conclusions:
MR-VWI may be useful in the evaluation of ruptured cranial dAVFs. In particular, it may aid in site-of-rupture identification. These findings support an emerging paradigm that spontaneously ruptured, macrovascular structures, e.g., intracranial aneurysms and venous varices, demonstrate avid vessel wall enhancement. The accurate identification of the ruptured vascular substructure may inform clinical decision-making.

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