Status post SRS for left cerebral vascular malformation in May 2015: surveillance. MRI: There is interval appearance of an irregularly rim-enhancing lesion measuring up to approximately 20 mm surrounding the site of the treated left temporo-occipital region arteriovenous malformation. There is increase in the extent of surrounding vasogenic edema. However, the anomalous vessels are less conspicuous. There is no evidence of acute intracranial hemorrhage or acute infarct. The ventricles and basal cisterns are normal in size and configuration. There is no midline shift or herniation. The orbits, skull, paranasal sinuses, and scalp soft tissues are grossly unremarkable.MRA: There is no discernible arterialized flow within the nidus of the arteriovenous malformation. There is no evidence of significant steno-occlusive lesions in the regular cerebral arteries. There is no evidence of aneurysms.
Interval development of radiation necrosis at the site of the treated left temporo-occipital region arteriovenous malformation, with associated surrounding vasogenic edema. The nidus of the arteriovenous malformation appears to have thrombosed.