Steady cerebral blood flow (CBF) is needed for normal brain function, but continuous monitoring of CBF in humans is currently challenging. Here, by leveraging a low-cost sensor technology, we introduce a class of novel near-infrared optical devices that monitor CBF continuously and non-invasively in adult humans. We achieve this by replacing expensive single photon counting detectors, currently used for optical CBF monitors, with complementary metal–oxide–semiconductor (CMOS) arrays. We maintain performance by employing an additional optical “trick” known as interferometry, which transforms each CMOS pixel into a sensitive detector for fluctuations of coherent light that probes blood flow in the brain. Our method is called interferometric Diffusing Wave Spectroscopy (iDWS). In this talk we describe technical advantages of iDWS, including recent advances in our approach, and broadly envisage how interferometry can help to advance the field of diffuse optical brain monitoring.
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