Radiation-induced change after Gamma Knife radiosurgery for cerebral arteriovenous malformations

Abstract

Objective: Radiation-induced change (RIC) on magnetic resonance imaging after Gamma Knife radiosurgery (GKRS) for cerebral arteriovenous malformations (AVMs) is not rare. We reviewed patients who underwent GKRS for AVMs and analyzed the results and factors associated with RIC.Methods: We reviewed 189 patients who underwent GKRS for AVMs between October 2002 and August 2017. All patients were followed up for at least 3 years. This study included 111 males and 78 females (mean age, 39.63 years; range, 3–79 years). Nineteen patients underwent pre-GKRS embolization. Seventy-six patients had ruptured AVMs and 113 had unruptured AVMs. We analyzed obliteration and RIC occurrence rates. Several demographic and clinical factors were analyzed to determine the influence of AVM obliteration on RIC occurrence.Results: The overall obliteration rate (OR) was 72.49% (137/189) at the final follow-up. The actuarial OR was 55.5% 36 months after GKRS. The overall RIC occurrence rate was 28.04% (53/189), and the actuarial RIC occurrence rate was 26.8% 24 months after GKRS. The OR showed a statistically significant difference according to AVM rupture (p<0.01) and sex (p<0.01). The RIC occurrence rate was significantly associated with AVM rupture (p<0.01), lesion volume (p=0.04), and treatment volume (p=0.03). Other factors showed statistically non-significant relationships.Conclusion: The overall OR after GKRS for AVMs was comparable to the results of other previous reports. RIC is a common postoperative outcome following GKRS for AVMs. In this study, the OR was higher in ruptured AVMs and male patients, whereas RIC occurred more frequently in larger and unruptured AVMs.