Optical visualization of blood shear stress using laser Doppler velocimetry combined with acousto-optic module

An acousto-optic modulator (AOM) was used in combination with two-beam multipoint laser Doppler velocimetry (MLDV) to achieve advanced blood flow observation for simultaneous determination of the magnitude and direction of the blood flow velocity. To measure the shear stress around the blood vessel wall, especially in regions near obstructions, the shear rate (velocity gradient) in a pulsatile blood flow was measured using the AOM in combination with two-beam MLDV (AOM-MLDV). In addition, the blood viscosity was measured using a rotating viscometer for the estimation of shear stress. Based on the measurement results, the shear stress could be estimated as the product of the viscosity and the shear rate, which was identified determined from the velocity distribution. The blood flow velocity was found to increase in the region around the obstruction in the flow channel. Complex flows formed as a result of the obstruction, and the shear stress was observed to reach a peak value around the obstruction based on the AOM-MLDV results. This paper presents a novel blood flow detection system that provides real-time state determination capabilities using acousto-optic modulation and LDV.

Automated summary

The study combined an acousto-optic modulator with two-beam multipoint laser Doppler velocimetry to observe blood flow velocity. The shear rate in pulsatile blood flow was measured to estimate shear stress, with the blood viscosity also considered. Results showed increased blood flow velocity and peak shear stress around obstructions. The research presents a novel blood flow detection system using acousto-optic modulation and LDV with real-time state determination capabilities.