Diffuse correlation spectroscopy for non-invasive, micro-vascular cerebral blood flow measurement

Abstract

Diffuse correlation spectroscopy (DCS) uses the temporal fluctuations of near-infrared (NIR) light to measure cerebral blood flow (CBF) non-invasively. Here, we provide a brief history of DCS applications in brain with an emphasis on the underlying physical ideas, common instrumentation and validation. Then we describe recent clinical research that employs DCS-measured CBF as a biomarker of patient well-being, and as an indicator of hemodynamic and metabolic response to functional stimuli.

Near-Infrared Spectroscopy in the Monitoring of Adult Traumatic Brain Injury: A Review

“…This technique has been largely pioneered at the University of Pennsylvania in Philadelphia. 53 The advantages of this technique are clear, as information regarding the supply/quantity of blood actually reaching the tissue and the saturation of the transported Hb with oxygen gives far more specific feedback as to the effects of any intervention or therapy. Further, it also supplies the clinician with a more detailed idea as to how ICP and cerebral perfusion are affecting oxygen delivery at the capillary level.…”

Modified Beer-Lambert law for blood flow

“…In total, this research has discovered new indicators of tissue function and health that are proving to be clinically relevant [6][7][8][9][10][11][12][13][14]. The most basic DOS/NIRS instrument measures diffuse reflectance from tissue as a function of input wavelength, and thereby derives the concentration of tissue chromophores and contrast agents, including oxyand deoxy-hemoglobin (HbO 2 , Hb), and changes thereof.…”

“…The most basic DOS/NIRS instrument measures diffuse reflectance from tissue as a function of input wavelength, and thereby derives the concentration of tissue chromophores and contrast agents, including oxyand deoxy-hemoglobin (HbO 2 , Hb), and changes thereof. Diffuse correlation spectroscopy (DCS), by contrast, is a more recently developed optical technique that utilizes the temporal intensity fluctuations of multiply scattered light in order to quantify microvascular blood flow in highly scattering tissues [13][14][15]. Like DOS/NIRS, the DCS method is non-invasive and penetrates tissue deeply, but DCS also offers the possibility to directly measure the "blood flow" contribution to tissue hemodynamics, continuously and at the bedside.…”

In-vivo multilaboratory investigation of the optical properties of the human head

“…[1] In particular, optical methods like fast optical signal (FOS) [2,3], diffuse correlation spectroscopy (DCS) [4] and functional near infrared spectrosocpy (fNIRS) [5][6][7] use red and near infrared light (e.g. 600-900 nm) to noninvasively investigate brain structures and brain functions, and proved to be complementary to existing neuroimaging techniques like electroencephalography, functional magnetic resonance imaging or positron emission tomography.…”