Arteriovenous malformation

There is a large, AVM involving the majority of the right hemisphere. In maximal dimension the nidus of the AVM covers approximately 8.8 cm and involves nearly the entire right parietal lobe and portions of the occipital and temporal lobe. Essentially all intracranial vessels appear to have some supply to the AVM as they are all dilated. The largest of these are the posterior cerebral arteries and the right middle cerebral artery. In addition, there are transcalvarial vessels supplying it via the occipital arteries bilaterally. These pierce the calvarium in the right parietal region.

There are multiple venous varices. The largest of these varices measure approximately 2.5 cm in maximal axial dimension. There are several other venous varices and aneurysms noted. The next most prominent of these is in the right temporal region measuring approximately 1 cm in diameter.

DSA reveals 2 separate AVM niduses that are complex.

The right parieto-occipital AVM nidus measure 5.5 x 4.7 x 3.3 cm with arterial feeders from the right anterior cerebral artery (via a left anterior communicating artery), left accessory middle meningeal artery, and a right posterior cerebral artery. The venous drainage for this nidus includes the vein of Galen and straight sinus.

The other nidus is within the right temporo-parietal region and measures 6.0 x 3.3 x 2.9 cm. Arterial feeders to this nidus includes the right middle cerebral artery and the right occipital and middle meningeal arteries. The venous drainage is mostly superficial, including cortical veins draining into the sagittal sinus.