Delayed Perilesional Ischemic Stroke after Gamma-knife Radiosurgery for Unruptured Deep Arteriovenous Malformation: Two Case Reports of Radiation-induced Small Artery Injury as Possible Cause

Radiation-induced vasculopathy is a rare occurrence, however, it is one of the most serious complications that can occur after gamma-knife radiosurgery (GKRS). The authors present two cases of incidentally found deep cerebral arteriovenous malformation (AVM), which were treated by GKRS, where subsequently there occurred delayed-onset cerebral infarction (11 and 17 months after GKRS) at an area adjacent to the AVM. In both cases, perforators of the M1 segment of the middle cerebral artery were included in the radiation field and delayed injury to these is suggested to be the mechanism of the ischemic event.