Investigating the effect of limited spectral information on NIRS-derived changes in hemoglobin and cytochrome-c-oxidase concentration with a diffusion-based model

Georgina Leadley; Robert J Cooper; Topun Austin; Jeremy C Hebden; Gemma Bale

doi:10.1364/BOE.531775

Investigating the effect of limited spectral information on NIRS-derived changes in hemoglobin and cytochrome-c-oxidase concentration with a diffusion-based model

Biomed Opt Express. 2024 Sep 17;15(10):5912-5931. doi: 10.1364/BOE.531775. eCollection 2024 Oct 1.

Authors

Georgina Leadley^{1

2

3}, Robert J Cooper³, Topun Austin¹, Jeremy C Hebden³, Gemma Bale^{2

4}

Affiliations

¹ Department of Paediatrics, University of Cambridge, UK.
² Department of Engineering, University of Cambridge, UK.
³ Department of Medical Physics and Biomedical Engineering, University College London, UK.
⁴ Department of Physics, University of Cambridge, UK.

Abstract

This paper investigates the theoretical capability of near-infrared spectroscopy (NIRS) systems to accurately measure changes in the oxidation state of cerebral cytochrome-c-oxidase (CCO) alongside the hemoglobins, for a deeper understanding of NIRS limitations. Concentration changes of oxy and deoxyhemoglobin (HbO and HbR) indicate the oxygen status of blood vessels and correlate with several other physiological parameters across different pathologies. The oxidation state of CCO indicates cellular energy usage efficiency through oxidative metabolism, potentially serving as a biomarker for brain and other tissue disorders. This study employs an analytical model based on the diffusion equation and statistical analyses to explore the dependency of estimated concentration changes on various systematic parameters, such as choice of wavelengths, spectral bandwidth, and uncertainties in extinction coefficient (ε) and differential pathlength factor (DPF). When there is a 10% uncertainty in DPF and ε, errors were found to be highly dependent on the number of discrete wavelengths, but not on their bandwidth if appropriate considerations are taken to account for it.