Histologic analysis of brain
Braak stage of 0 and Thal stage of 0 (for, vascular diseases, non-AD
VASCULAR DISEASES, BRAIN, CORTEX
Due to limited feasibility of perivenous space characterization by histology in live humans, postmortem tissues from elderly non-trial AD subjects and age-matched non-trial, non-AD decedents were examined histologically to further understand the MRI effects. Routine hematoxylin and eosin-stained slides corresponding to the superior frontal, parietal precuneus, and medial temporal brain regions were analyzed from three subjects per group. Brain samples sustained postmortem intervals of 48 h or less and were selected from hospital decedents without documented vascular diseases (including CAA), and with Braak stage of 0 and Thal stage of 0 (for non-AD group) or Braak stage of 4 and Thal stage of 3 or 4 (for AD group). Samples were prepared per standard protocol including 12 days of formalin fixation followed by paraffin embedment, six micron sectioning, and routine staining. Mean patient age was 65 years (age range, 64 to 67 years). Perivenous regions in cerebral cortex and subcortical white matter were evaluated on each slide by routine histologic and light microscopic techniques to assess the nature of perivenous microanatomy and potential flow paths visualized by in vivo MRI. Histological analysis was conducted by a licensed and experienced, board-certified academic neuropathologist expert on neurovascular anatomy and age-related brain changes.