Relief of hemiballism from a basal ganglia arteriovenous malformation after radiosurgery

A patient with a 3-year history of progressive hemiballism presented with a n unruptured arteriovenous malformation (AVM) in the contralateral caudate nucleus and putamen. PET demonstrated a matched reduction of cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) in the basal gang lia and adjacent frontal lobe. The patient underwent radiosurgery for the A VM. After a period of no clinical change for 6 months, the movement disorde r resolved by month 7 post-treatment. The AVM was successfully obliterated 2 years after irradiation without any significant change in the regional CB F or CMRO2.