Pulsatile microvascular blood flow imaging by short-time Fourier transform analysis of ultrafast laser holographic interferometry

TL;DR

This paper introduces a high-resolution, real-time imaging technique for pulsatile microvascular blood flow in the mouse brain cortex using holographic interferometry combined with short-time Fourier transform analysis.

Contribution

It presents a novel method for wide-field, instantaneous imaging of pulsatile blood flow with high spatial and temporal resolution in vivo.

Findings

Successful visualization of pulsatile blood flow in superficial vessels

High spatial resolution of 10 microns achieved

Temporal resolution of 20 milliseconds demonstrated

Abstract

We report on wide-field imaging of pulsatile microvascular blood flow in the exposed cerebral cortex of a mouse by holographic interferometry. We recorded interferograms of laser light backscattered by the tissue, beating against an off-axis reference beam with a 50 kHz framerate camera. Videos of local Doppler contrasts were rendered numerically by Fresnel transformation and short-time Fourier transform analysis. This approach enabled instantaneous imaging of pulsatile blood flow contrasts in superficial blood vessels over 256 x 256 pixels with a spatial resolution of 10 microns and a temporal resolution of 20 ms.