2bNIRS: a portable, multi-distance, broadband oximeter and cytochrome-c-oxidase monitoring system for in vivo applications

TL;DR

The paper introduces 2bNIRS, a portable broadband NIRS system capable of monitoring tissue oxygenation and metabolism in vivo, validated through phantom and human studies, with improved accuracy over traditional methods.

Contribution

A novel compact broadband NIRS device with advanced spectral fitting and spatial analysis, enabling simultaneous tissue oxygenation and metabolic monitoring in vivo.

Findings

Validated accuracy in phantom experiments for haemodynamic and metabolic tracking.

Demonstrated in vivo monitoring of muscle and brain tissue during physiological challenges.

Achieved superior oximetry performance with the BRUNO algorithm.

Abstract

Conventional near-infrared spectroscopy (NIRS) instruments typically employ 2-3 wavelengths for monitoring tissue haemodynamics. However, the use of broadband illumination (hundreds of wavelengths) unlocks also the targeting of tissue metabolism by exploiting the wide differential-redox peak of absorption of cytochrome-c-oxidase (CCO). For this purpose, we present here a novel, broadband (780-900nm), multi-distance NIRS system, called 2bNIRS. Compact and portable (20 x 30 x 40 cm3), 2bNIRS was validated using a dynamic, optical phantom con-taining blood and yeast, and benchmarked against a multi-wavelength time-domain NIRS (TD-NIRS) system. Validation confirmed its accuracy in tracking haemody-namic and metabolic changes, with superior oximetry performance achieved via our BRUNO algorithm, which integrates broadband spectral fitting with spatially-re-solved analysis. Preliminary in vivo, human applications demonstrated 2bNIRS ap-plicability to monitoring both muscle tissue, during arm cuff occlusions, and the brain, during frontal cortex activation.