A Novel Portable and Wearable Broadband Near-Infrared Spectroscopy Device for In-Vivo Oxygenation and Metabolism Measurements

TL;DR

This paper introduces microCYRIL, a portable broadband NIRS device that enables in-vivo oxygenation and metabolism measurements by miniaturizing spectrometer and LED technology for clinical use.

Contribution

The paper presents the first portable, miniaturized broadband NIRS device capable of dual-channel oxygenation and metabolism measurements, utilizing innovative photonic components.

Findings

Successfully tracked hemoglobin concentration changes during occlusion

Demonstrated device functionality for in-vivo oxygenation measurements

Achieved miniaturization enabling portability of broadband NIRS

Abstract

Broadband NIRS (bNIRS) is an extension of fNIRS that provides the same assessment of oxygenation biomarkers along with a valuable marker for oxygen metabolism at a cellular level, the oxidation state of cytochrome-c-oxidase (oxCCO). bNIRS implements many (100s) NIR wavelengths in the full NIR spectrum to address this and provide insight to tissue energetics. To supply these many wavelengths of light, broadband sources are required, and spectrometers are employed to distinguish power per wavelength. Current multi-channel bNIRS instruments are bulky and only semi-portable due to technological limitations. We propose a design for a bNIRS device that has been miniaturized to allow for portable use. This design leverages the innovations in photonic devices that have created a new line of microspectrometers and broadband NIR high-power LEDs; the Hamamatsu SMD-type spectrometer C14384MA and the Ushio SMBBIR45-1100 LED. This first-of-itskind device, referred to as microCYRIL (after its two predecessors CYRIL and miniCYRIL), has been developed for oxygenation and metabolism measurements with dual channel operation. To verify functionality, concentration changes in oxygenated (HbO2) and deoxygenated (HHb) haemoglobin and oxCCO were successfully tracked during a cuff-induced venous and arterial occlusion.