Vessel wall enhancement of a ruptured intra-nidal aneurysm in a brain arteriovenous malformation

Abstract

Ruptured arteriovenous malformations are a frequently encountered pathology with significant associated morbidity and mortality. Identifying and securing the rupture point is mandatory; however, this can often be difficult. Black blood vessel wall magnetic resonance imaging is a promising technique for identifying ruptured saccular aneurysms and has been used in cases of multiple aneurysms. Here we describe a case of using this imaging technique to identify the rupture point in a ruptured arteriovenous malformation with histopathological correlation.

Keywords: AVM; haemorrhage; histology; vessel wall enhancement.

Figure 1.

(a) The unenhanced axial computed tomography (CT) scan demonstrates intraventricular haemorrhage with several foci of calcification within the right frontal lobe. A CT angiogram demonstrates a right frontal arteriovenous malformation with an aneurysm directed into the right frontal horn of the lateral ventricle that was believed to be the source of the haemorrhage (b and c).

Figure 2.

A magnetic resonance image with pre and post-contrast T1-weighted sequences was performed. The aneurysm demonstrated on the computed tomography angiogram was clearly visible on the pre-contrast T1-weighted sequences (a and c, white arrow) with thick, circumferential enhancement of the aneurysmal wall seen on the post-contrast sequences (b and d, white arrow). There was no significant enhancement seen elsewhere within the arteriovenous malformation.

Figure 3.

Catheter angiography of the right internal carotid artery demonstrated supply to the arteriovenous malformation from branches of the middle cerebral artery (a and b) with a medially directed aneurysm that correlated with the enhancing aneurysm seen on magnetic resonance imaging that was clearly appreciated on intra-arterial rotational angiography (c).

Figure 4.

At the end of the embolisation procedure persistent filling of the superior component of the arteriovenous malformation (AVM) was noted and further endovascular embolisation was not deemed feasible (a). The patient underwent resection for the residual AVM. A postoperative computed tomography scan showed successful resection of the AVM, with the embolised aneurysm still demonstrable adjacent to the right frontal horn.

Figure 5.

Arteriovenous malformation demonstrating classic histological appearances of (a) closely associated, sometimes tortuous, ectatic vascular channels with walls of varying thickness and size. Occasional vessels contain black-staining embolisation material (Onyx) (b). Several vessel walls contain prominent internal elastic laminae, which are demonstrated on Masson trichrome staining as dark staining within the vessel walls (c). A higher power representative view demonstrating no histological evidence of mural inflammatory cell infiltrate within the vessel walls (d).