Imaging cerebral blood flow for brain health measurement

Cerebral blood flow (CBF) measures are used in clinical settings to diagnose conditions (e.g., vasospasms, sickle cell disease, stroke, dementia, confirmation of brain death), as well as in research, emerging as potential early biomarkers of declining brain health. The aim of this chapter is to provide an overview of approaches used to measure CBF for determining resting cerebral tissue perfusion and functional CBF responsiveness. We will highlight the strengths and weaknesses of each and illustrate the methodological differences that need to be considered when assessing brain vascular health. The imaging methods measuring CBF will cover: Doppler ultrasound (spanning transcranial Doppler (TCD), duplex ultrasound, and transcranial color Doppler (TCCD)), magnetic resonance imaging (MRI) (including arterial spin labeling (ASL), blood oxygenation level dependent (BOLD) signal measures and phase-contrast angiography), and finally near-infrared spectroscopy (NIRS).