A 39-year-old right-handed schoolteacher was evaluated for recurrent ischemic strokes and inability to read.

Six months prior to her evaluation, our patient noticed anxiety and inability to sleep. She had increased blood pressure and felt “not herself.” She also complained of “inability to see well” and of a “slow thought processing.” A month later, she could not find words, and her speech became slurred. She realized she had difficulty with reading but not with writing.

Her brain MRI showed areas of restricted diffusion in the left cerebral hemisphere and splenium of the corpus callosum. There was subtle enhancement on the left hippocampus anteriorly as well as high T2 and FLAIR signal abnormalities in the posterior lateral aspect of the left thalamus and probably a few small foci on the right cerebral hemisphere. MRA showed scattered vessel irregularity with multiple areas of narrowing involving the ACA, MCA, and PCA bilaterally, with more severe stenosis involving the proximal portion of the left PCA and the proximal portion of the A1 segment of the left ACA. The cervical carotid artery bifurcations were normal. Cerebrospinal fluid and numerous additional ancillary investigations were negative for systemic vasculitis, hypercoagulable states, or cardioembolic disorders. Catheter cerebral angiography showed multiple areas of segmental arterial narrowing in the distal left MCA and left ACA branches; multiple areas of segmental arterial narrowing in the distal right MCA and right ACA branches; and segmental arterial narrowing of both PCAs, worse on the left P1 and P2 segments, with 70% stenosis associated with reduced flow in the PCAs, left greater than right (Fig. 50.1).