Establishing the quantitative relationship between diffuse speckle contrast analysis signals with absolute blood flow

Jialin Liu,Hongchao Zhang,Zhiliang Jin,Peipei Wang,Daxi Xiong,Weimin Li,Haiyang Wang,Zhonghua Shen

doi:10.1364/boe.9.004792

Abstract

Diffuse speckle contrast analysis (DSCA) measures blood flow in deep tissues by taking advantage of the sensitivity of the speckle contrast signal to red blood cells (RBCs) motions. However, there has yet to be presented a clearly defined relationship between the absolute blood flow BFabs and the measured speckle contrast signal. Here, we derive an expression of linear approximation function for speckle contrast, taking into account both shear-induced diffusive and correlated advective RBCs motions in the vessels. We provide a linear relationship between the slope k slope of this linear function and BFabs. The feasibility of this relationship is validated by Monte Carlo simulations of heterogeneous tissue with varying vessel radii. Furthermore, based on this quantitative relationship, we can determine the relative contributions of diffusive RBCs motion on the reduction of speckle contrast, considering different vascular morphology and flow profiles.

Highlights

Several optical approaches have been used for non-invasive blood flow measurements for the last several decades, in either single or multiple scattering regimes
The former technique, known as laser speckle contrast imaging (LSCI) [1,2,3,4], uses the spatio-temporal blurring of the speckle imaging defined as speckle contrast K to measure blood flow information in superficial tissues
Based on Brownian motion model, we have developed and tested a thorough speckle contrast model [26,27,28] in Diffuse speckle contrast analysis (DSCA) for quantitative measurement of the red blood cells (RBCs) motion

Summary

Introduction

Several optical approaches have been used for non-invasive blood flow measurements for the last several decades, in either single or multiple scattering regimes The former technique, known as laser speckle contrast imaging (LSCI) [1,2,3,4], uses the spatio-temporal blurring of the speckle imaging defined as speckle contrast K to measure blood flow information in superficial tissues. LSCI is performed by the illumination of the biological tissue with a coherent light source and imaging of the reflected speckle by a camera. This technique allows the use of a simple experimental setup with the advantages of a relatively high spatiotemporal resolution, but under the condition of single or few scattering events it limits the photon penetration depth in the tissue [5]. To obtain a higher signal-to-noise (SNR), it is necessary to use multiple detectors to simultaneously acquire multiple independent speckles, which results in the increasing of the cost and complexity of DCS

Results

Discussion

Conclusion