Mapping of cerebro-vascular blood perfusion in mice with skin and skull intact by Optical Micro-AngioGraphy at 13µm wavelength

Ruikang K Wang,Sawan Hurst

doi:10.1364/oe.15.011402

Abstract

Optical micro-angiography (OMAG) was developed to achieve volumetric imaging of the microstructures and dynamic cerebrovascular blood perfusion in mice with capillary level resolution and high signal-to-background ratio. In this paper, we present a high-speed and high-sensitivity OMAG imaging system by using an InGaAs line scan camera and broadband light source at 1.3 mum wavelength for enhanced imaging depth in tissue. We show that high quality imaging of cerebrovascular blood perfusion down to capillary level resolution with the intact skin and cranium are obtained in vivo with OMAG, without the interference from the blood perfusion in the overlaying skin. The results demonstrate the potential of 1.3 mum OMAG for high-speed and high-sensitivity imaging of blood perfusion in human and small animal studies.

Highlights

The ability to accurately visualize micro-vascular networks under normal and diseased conditions is critical for evaluating the emerging therapeutic strategies, such as in the development of potential drugs to support or limit neovascular growth [1]
We demonstrate a high-speed, high sensitivity Optical micro-angiography (OMAG) imaging system operating at a central wavelength of 1.3μm for maximum imaging depth in tissue
To assess the imaging performances afforded by OMAG, we conducted a series of experiments

Summary

Introduction

The ability to accurately visualize micro-vascular networks under normal and diseased conditions is critical for evaluating the emerging therapeutic strategies, such as in the development of potential drugs to support or limit neovascular growth [1]. The introduction of fM in the interferograms was achieved by linear translation of the reference mirror in the interferometer, synchronized with the OCT cross-sectional (B scan) imaging This makes it possible to separate the light scattering signals backscattered from the moving particles, such as moving blood cells, from those backscattered from the static particles, such as bulk tissue, leading to high resolution mapping of dynamic blood perfusion down to capillary levels within thick tissue sample in vivo. Previous investigations in the development of OCT have shown that, for a highly scattering biological tissue, enhanced imaging depth for light source centered at ~1300nm wavelength can be resulted when compared to that centered at ~820nm [21,22,23] This conclusion holds for OMAG imaging modality. To the best of our knowledge, since the development of OCT, this is the first time that trans-dermal and trans-cranial cerebral blood perfusion can be imaged in 3D at the capillary level resolution

OMAG system setup

Performance assessment

In vivo mouse imaging results

Conclusions