CNS arteriovenous malformation (AVM)

Findings

There is a large, diffuse left cerebral hemisphere arteriovenous malformation, which is located mostly within the posterior left frontal lobe. The remainder of the brain parenchyma appears within normal limits. On the MR angiogram, there is a large left frontal and parietal lobe mass of tangled vessels supplied mostly by left MCA, but also left ACA branches. On the conventional angiogram, there is a tangle of vessels in the left parietal lobe, with arterial supply from the prefrontal and post frontal branches of the Rolandic division. There is venous drainage drainage into the superior sagittal sinus and sphenoparietal sinus.

Diagnosis: CNS arteriovenous malformation


Key points

Classic imaging finding is "bag of worms" from flow voids.
Minimal or no mass effect.
Strong enhancement on CT.
MRI characteristics varies with flow rate and presence / age of hemorrhage.
Peak presentation between 20 and 40 years old.
50% will hemorrhage; 25% will have seizures.
Rare spontaneous regression.
Treatment includes embolization, radiosurgery, and also surgical resection.