Stereotactic radiosurgery for arteriovenous malformations: 1-year follow-up

To define treatment factors related to early obliteration of arteriovenous malformations (AVMs), we followed 71 patients treated using the gamma knife for 1 year. Abnormal signal intensity suggesting radiation-induced change was demonstrated on MRI in 11 of 42 patients examined; only 1 showed neurological deterioration. Neurological impairment observed in 5 of the 71 patients was associated with rebleeding. This result supports the importance of early AVM obliteration. Total obliteration was confirmed in 18 of 60 patients examined. Higher peripheral doses were given smaller treatment volumes using higher peripheral isodense levels in the patients with total obliteration. Early obliteration could be expected in the patients treated with effective irradiation parameters.