Presentation
Recurrent headaches and seizures over the past several months, accompanied by nausea and vomiting, paresthesia, and loss of sensation in the left arm
Patient Data
There are numerous well-delineated hyperdense curvilinear structures and macroscopic calcifications with no mass effect on the adjacent brain. The abnormality is primarily located in the right frontoparietal region.
Multiple flow voids on T2, with some areas of gliotic brain parenchyma appearing hyperintense. Despite its size, there is no mass effect. T2*-weighted images demonstrate foci of blooming within the lesion, which correlates to calcification observed in the CT and probably areas of hemorrhage. The main feeding vessel is the right middle cerebral artery (seen on both T2 and MRA), which is markedly enlarged. The ACA is also enlarged and is therefore also supplying the AVM. The large nidus is observed in the right frontal-parietal region.
Venous drainage is primarily superficial.
Catheter angiography is required to fully characterize the lesion.
Case Discussion
MRI imaging plays a critical role in the evaluation and diagnosis of brain arteriovenous malformations.
This case demonstrates classic MRI findings of an AVM 1-4 :
tightly packed masses or "honeycomb" flow voids on T1 and T2 scans
brain parenchyma is gliotic and hyperintense on T2WI and FLAIR
common presence of hemorrhagic foci
T2* sequences show "blooming" foci within and around AVMs and adjacent pia siderosis