Abstract
The experiences of the first 144 cases of arteriovenous malformation (AVM) treated with the gamma knife at the University of Tokyo Hospital between June 1990, and May 1992 are described. One year after radiosurgery, complete obliteration was observed in 16 (31.4%), remarkable decrease in 7 (13.7%), and partial obliteration in 24 (47.1%) of 51 patients who underwent angiography. There seems to be a tendency for smaller AVMs to be obliterated earlier. The minimal dose at the periphery required for total obliteration was estimated to be 20Gy. Bleeding after radiosurgery was observed in 5 (3.5%) cases. The bleeding rate was higher for AVMs located close to ventricles. Nine (13.2%) of 68 patients showed neurological deterioration three to twelve months after radiosurgery. A low density area on CT was demonstrated in ten (17.5%) of 57 patients. These outcomes are compatible with previous reports and confirm the efficacy of stereotactic radiosurgery for cerebral arteriovenous malformations.
