Vessel wall MRI in ruptured cranial dural arteriovenous fistulas

Abstract

Intracranial high-resolution vessel wall MRI (VW-MRI) is an imaging paradigm that is useful in site-of-rupture identification in patients presenting with spontaneous subarachnoid hemorrhage and multiple intracranial aneurysms. Only a handful of case reports describe its potential utility in the evaluation of more complex brain vascular malformations. We report for the first time three patients with ruptured cranial dural arteriovenous fistulas (dAVFs) that were evaluated with high-resolution VW-MRI. The presumed site-of-rupture was identified based on contiguity of a venous ectasia with adjacent blood products and thick, concentric wall enhancement. This preliminary experience suggests a role for high-resolution VW-MRI in the evaluation of ruptured cranial dAVFs, in particular, site-of-rupture identification. It also supports an emerging hypothesis that all spontaneously ruptured, macrovascular lesions demonstrate avid vessel wall enhancement.

Keywords: Dural arteriovenous fistula; magnetic resonance; vessel wall MRI.

Figure 1.

A 39-year-old man with a ruptured dAVF of the hypoglossal canal. (a) CT scan (sagittal reconstruction) demonstrates acute SAH in the cerebello-medullary cistern (arrow). (b) CTA (sagittal reconstruction) demonstrates regional abnormal vascularity with a conspicuous, aneurysmal vascular out-pouching (arrow). (c) Selective injection of the ascending pharyngeal artery (DSA, lateral projection) confirms a dAVF of the hypoglossal canal. The conspicuous aneurysmal vascular structure corresponds to a venous ectasia (arrow). (d) Superselective, microcatheter injection of the hypoglossal branch of the ascending pharyngeal artery (DSA, lateral projection) better demonstrates the venous ectasia (arrow). (e) High-resolution black blood T1WI before the administration of gadolinium demonstrates hyperintense blood product contiguous with the inferior wall of the venous ectasia (arrow) consistent with the presumed site-of-rupture. (f) High-resolution black blood T1WI after the administration of gadolinium demonstrates selective, thick, concentric enhancement of the venous ectasia wall (arrow).

Figure 2.

An 87-year-old woman with a ruptured cerebellar dAVF. (a) CT head demonstrates a midline cerebellar hematoma with associated SAH. (b) CTA demonstrates a conspicuous, bi-lobed venous varix adjacent to the midline cerebellar hematoma. (c) High-resolution black blood T1WI before the administration of gadolinium demonstrates contiguity of the anteriorly-projecting lobe of the venous varix (short arrow) with the cerebellar hematoma (long arrows), but not the posteriorly-projecting lobe (asterisk). Post-contrast images (insets) demonstrate circumferential enhancement of the anterior, but not posterior, lobe of the ruptured venous varix.

Figure 3.

A 54-year-old man with a ruptured cranial dAVF. (a) Admission CT head demonstrates an acute subdural hematoma (SDH) with associated midline shift. Note was made of a small, contiguous intraparenchymal hemorrhage (long arrow) with central ghosting. (b, c) DSA was performed post-craniectomy for evacuation of the SDH. Selective injection of the occipital artery ((b) anteroposterior projection; (c) lateral-oblique projection) demonstrates a Borden type III cranial dAVF with significant cortical venous reflux subjacent to the evacuated SDH. (d, e) High-resolution black blood T1WI before the administration of gadolinium ((d) axial; (e) coronal) demonstrates a prominent bi-lobed venous varix at the base of the intraparenchymal hematoma (long arrow). Note the surrounding hyperintense blood product contiguous with the ruptured venous varix. Post-contrast images (insets) demonstrate selective, thick, concentric enhancement of the medially-projecting bleb (arrowhead). (f, g) Magnified views of the ruptured venous varix before (f) and after (g) the administration of gadolinium (corresponding to panel (e)).