Figure 4. Example patient images.

(A) Atherosclerotic patient example. Digital subtraction angiography (DSA) demonstrates severe left M1 stenosis, which is successfully treated with stent placement. Four months after stent placement, in-stent restenosis is significant. Diffusion weighted imaging (DWI) demonstrates watershed infarcts related to severe M1 stenosis. After stent placement, lumenal stenosis is not directly evaluated by computed tomography angiography, but is inferred from decreased opacification of left M2 branches. Blood oxygenation level-dependent (BOLD) cerebrovascular reactivity (CVR) was performed two years after stent placement, when angioplasty was considered due to patient’s increasing dysarthria. CVR is markedly reduced in the left MCA territory with negative z-statistic. (B) Moyamoya patient example. Pre-operatively, although DSA from left internal carotid artery (ICA) injection demonstrates bilateral moyamoya disease (mSS=3 on right; mSS=2 on left), and only prior infarct is in left caudate head on FLAIR, BOLD CVR is markedly reduced in the right cerebral hemisphere, thus indirect revascularization with encephaloduroarteriosynangiosis (EDAS) was performed on the right. Revascularization response is demonstrated on CVR images over a three-year duration. Responses have been normalized by occipital Z-statistics (Z-stat_occ) to allow for comparison between time points.