抄録
We retrospectively studied 55 patients with asymptomatic cerebral arteriovenous malformation (AVM) in 34 men and 21 women aged 10 to 73 years (mean 42.7 years), who underwent gamma knife radiosurgery (GKS) at our hospital. The mean nidus volume was 6.6 cc (0.1-19.6 cc), and the mean prescription dose at the nidus margin was 20.4 Gy (12-26 Gy). The actuarial obliteration rate was 65.0% at 3 years and 81.0% at 5 years, based on angiography in 22 patients and magnetic resonance (MR) imaging in 16 patients.
Multivariate analysis showed that the delivered peripheral dose significantly correlated with obliteration rate (p=0.04). Twenty-three of the 55 patients developed radiation-induced change of brain tissue on follow-up MR imaging, and 6 of the 23 patients were symptomatic. Fourteen of 23 patients with edema of the brain tissue required steroid therapy. There was no permanent neurological complication. One of the 55 patients suffered postradiosurgical hemorrhage. No patient developed long-term complication such as cyst formation or chronic encapsulated expanding hematoma.
These findings suggest that GKS is effective for the treatment of asymptomatic cerebral AVM, especially if located in deep or eloquent areas. In contrast, we recommend direct surgery for AVM in surgically accessible regions because of the relatively high rate of radiation-induced change of brain tissue on follow-up MR imaging.
