This is an observational trial, in patients with moderate to severe anemia and control subjects. The main purpose of this study is to understand whether normal brain blood flow, oxygen extraction reserve, white matter volumes, and brain functional connectivity are affected by acquired anemia. The investigators will perform baseline MRI monitoring for all subjects. All eligible subjects will be asked to provide informed consent before participating in the study. Comprehensive cerebrovascular MRI, baseline bloodwork, and neurocognitive testing will be collected from all subjects.
