Stereotactic radiosurgery of cerebral arteriovenous malformations: Appearance of perinidal T₂ hyperintensity signal as a predictor of favorable treatment response

The purpose of this study was to analyze the significance of perinidal T₂ hyperintensity appearance after radiosurgery of arteriovenous malformations (AVMs), as a predictor of treatment response. Our initial experience with linear accelerator (LINAC) radiosurgery at University of California, Los Angeles, between 1990 and 1997 involved treatment of 129 patients affected by cerebral AVMs. Based upon availability of neuroimaging follow-up, 48 patients with 50 AVMs were selected for review. Forty (80%) of the AVMs underwent complete obliteration or significant reduction on follow-up MRI, on average 20 months after radiosurgery. Thirteen (72%) of 18 obliterated AVMs were associated with perinidal T₂ hyperintensity signal, on average 18 months (6-49) after radiosurgery. Ten (20%) of 50 AVMs (average volume 23.1 cm³, ranging 7.5-46.5) were unchanged. Furthermore, only 3 AVMs in this group showed reversible T₂ signal changes. In patients with complete nidal obliteration, appearance on T₂ hyperintensity signal achieves 72% sensitivity in predicting successful treatment response. Copyright (C) 2000 S. Karger AG, Basel.