Abstract
Gamma knife radiosurgery has become one of the major treatments for cerebral arteriovenous malformations (AVMs), especially, for deep-seated AVMs such as brain stem, basal ganglia and thalamus. However, a brain edema and/or bleeding following gamma knife radiosurgery are often observed in the follow-up period. We focused on AVMs in the basal ganglia and thalamus, and investigated the outcome of gamma knife radiosurgery. Among 85 AVMs treated by gamma knife radiosurgery and followed by MRI and/or angiography for more than 2 years, 22 AVMs were located in the basal ganglia and thalamus. The complete obliteration rate of these 22 AVMs was 54.5%, and radiation-induced edema was observed on MRI in 31.8%of these AVMs. In comparison with AVMs in the cerebral hemisphere, radiation-induced edema in the basal ganglia and thalamus frequently became symptomatic. Therefore, in the treatment of large AVMs in the basal ganglia and thalamus, other therapeutic modalities such as intravascular surgery before gamma knife treatment, fractionated irradiation, and low-dose irradiation should be considered.
