title: Clinical evaluation of gamma knife radiosurgery for intracranial arteriovenous malformation.
abstract: OBJECTIVE
  Aim of the study is to compare our treatment results or gamma knife radiosurgery for arteriovenous malformation (AVM) and to obtain factors determining nidus obliteration and/or adverse effect.
  
  
  METHODS
  We analyzed 236 patients with AVM treated between June 1990 and February 1994. The patients consisted of 137 men and 99 women, and ranged in age from 4 to 71 years. AVM volume ranged 0.7 to 37.7 ml. Maximum and peripheral doses ranged from 18.2 to 60.0 Gy and 10.0 to 28.0 Gy, respectively.
  
  
  RESULTS
  Complete obliteration rates at 1,2, and 3 years were 36.2, 68.9, and 86.6%, respectively. The mean time to complete obliteration was 21.4 months. Univariated analysis revealed that calculated target volume, peripheral dose, peripheral percent dose and treatment optimality were significant factors for complete obliteration. In multivariate analysis, calculated target volume, treatment optimality, and CT-based planning were significant factors. The actuarial risk of post-radiosurgical brain edema at 2 years was 20.0%. In both univariate and multivariate analysis, calculated target volume was the only significant factor. Symptomatic complications developed in 10.0% of patients at 2 years, but no significant factors were identified. Permanent complications and severe neurological deficits were seen in 4.4 and 2.8% of patients, respectively.
  
  
  CONCLUSIONS
  Our results were similar to those reported previously. Accurate CT-based planning contributed to an improved obliteration rate.
authors.affiliation: Department of Radiology, Faculty of Medicine, University of Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Aoki
authors.forename: K
authors.initials: K
authors.lastname: Nakagawa
authors.forename: M
authors.initials: M
authors.lastname: Tago
authors.forename: A
authors.initials: A
authors.lastname: Terahara
authors.forename: H
authors.initials: H
authors.lastname: Kurita
authors.forename: Y
authors.initials: Y
authors.lastname: Sasaki
mesh_terms: D000206:Actuarial Analysis; D000293:Adolescent; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001929:Brain Edema / Q000209:etiology; D002648:Child; D002675:Child, Preschool; D005069:Evaluation Studies as Topic; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009460:Neurologic Examination; D010347:Patient Care Planning; D016634:Radiosurgery / Q000009:adverse effects / Q000379:methods; D011879:Radiotherapy Dosage; D012074:Remission Induction; D012307:Risk Factors; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome