In vivo Measuring of Blood Flow Changes using Diffusing Wave Correlation Techniques

Abstract

In recent years there has been a growing interest in the study of flow phenomena in complex fluids using photon speckle correlation techniques 1, 2 . The best-known applications of these studies in biology and medicine are the non-invasive measurements of blood flow in large and small blood vessels, as well as the blood volume changes in capillary loops of muscles and other biological tissues In this contribution, methods for probing the spatially varying dynamics of blood flow in heterogeneous turbid media with diffusing light are applied. The method utilizes the Doppler broadening of light that arises in a multiply scattering dynamical media, but the method is also responsive to μa, μs’ changes. Specifically, we use correlation techniques to monitor blood flow in the arm during cuff ischemia. Our measurements clearly show blood flow changes with cuff pressures, including the hyperemic overshoot after cuff release. In this paper we describe experiments, and discuss the results with some theoretical explanation and correlation with physiological phenomena.