 There are postoperative findings related to left-sided craniotomy for STA-MCA bypass. There are expected postsurgical changes including small extra-axial fluid collection along the left cerebral hemisphere as well as small amount of pneumocephalus. There are multiple new small foci of restricted diffusion scattered in the left frontal lobe consistent with acute infarcts and new since previous MRI dated 10/22/2015. There is a relatively larger area of restricted diffusion along the left temporal lobe surface compatible with cytotoxic edema/infarct and may be likely related to retraction.There are increased areas of T1 hyperintensities in the left frontal and temporal lobe compatible with cortical laminar necrosis. Again seen are patchy and scattered high FLAIR signal intensity lesions in the bilateral periventricular and subcortical white matter, particularly in the left cerebral hemisphere, related to chronic ischemia. There are multiple lacunar infarcts in the bilateral basal ganglia.The ventricles are unchanged from prior. There is volume loss involving cerebellar hemispheres left more than right as seen before. There is no mass effect, midline shift or herniation. The midline structures and craniocervical junction are within normal limits.MRA head: Evidence of recent left-sided a STA-MCA bypass with focus of susceptibility at the bypass site. There is redemonstration of a chronic occlusion of the left internal carotid artery which is reconstituted at the level of the left supraclinoid ICA. There is atheromatous plaque involving cavernous and supraclinoid internal carotid arteries. There is moderate stenosis of the right supraclinoid ICA. There is mildly diminished flow-related signal involving the left MCA compared to the right MCA with prior CTA also demonstrating mildly reduced caliber of the left MCA compared to the right MCA. Anterior cerebral arteries are patent. Again seen is a 2.5 mm right anterior communicating artery aneurysm better seen on recent CTA. There is also approximately 5 mm outpouching along the right lateral cavernous internal carotid artery. Atherosclerotic disease is also evident involving the posterior circulation with mild multifocal stenosis affecting the distal vertebral, basilar artery and posterior cerebral arteries.
1. Postoperative findings related to left STA-MCA bypass. There is susceptibility artifact at the bypass site and CTA may be helpful if clinically warranted. There are multiple new foci of acute infarct in the left cerebral hemisphere. There is a relatively larger focus of restricted diffusion/infarct involving the left temporal lobe surface which may be related to retraction.2. Redemonstration of chronic occlusion of the left ICA with reconstitution in its supraclinoid segment. The left MCA demonstrates mildly diminished flow-related signal as compared to the right. There is moderate stenosis involving the right cavernous internal carotid artery.3. 2.5 anterior communicating artery aneurysm as well as a 5 mm right cavernous ICA aneurysm as seen on recent angiogram.4. Multiple prior infarcts, particularly in the left cerebral hemisphere.