A Compact Multi-Distance DCS and Time Domain NIRS Hybrid System for Hemodynamic and Metabolic Measurements

Abstract

In this work, we present a new multi-distance diffuse correlation spectroscopy (DCS) device integrated with a compact state-of-the-art time domain near infrared spectroscopy (TD-NIRS) device. The hybrid DCS and TD-NIRS system allows to retrieve information on blood flow, tissue oxygenation, and oxygen metabolic rate. The DCS device performances were estimated in terms of stability, repeatability, ability in retrieving variations of diffusion coefficient, influence of the tissue optical properties, effect of varying count rates and depth sensitivity. Crosstalk between DCS and TD-NIRS optical signals was also evaluated. Finally, in vivo experiments (venous and arterial cuff occlusions on the arm) were conducted to test the ability of the hybrid system in measuring blood flow variations.

Evaluation of muscle aging with TD NIRS and DCS

“…1, where the time courses for the hemodynamic and perfusion parameters during the arterial occlusion (panels a), b) and c)) and the incremental cycling exercise (panels d), e), f)) are shown. As expected 4 , during the occlusion HHb progressively increases while HbO2 decreases. Thus, tHb shows a slight increase, and StO2 exhibits an almost linear reduction.…”

“…At the end of the exercise, a cool-down period with light pedaling was performed. All the measurements were performed using a device previously developed at the Physics Department, Politecnico di Milano, which allows TD NIRS and DCS synchronized acquisitions 4 . During all protocols, the custom-made probe, hosting TD-NIRS and DCS optical fibers, was placed on the vastus lateralis muscle and fixed with a black auto-adhesive bandage.…”

Filament 3D printing technology for diffuse optics applications: advantages and drawbacks

“…For the DCS measurements, we used a device developed by the same authors [3]: highly coherent laser light (784 nm) with maximum nominal power of 120 mW was employed as injection source, and a single mode fiber led the reemitted light to the detection channel. The interfiber distance used for the DCS measurements was 1.5 cm, and optical prisms were used for bending both the injected and detected photons.…”

A Contact-Sensitive Probe for Biomedical Optics

“…Optical probes for fiber-based NIRS systems are typically made of flexible 3D-printed materials that incorporate the injection and detection fibers and accommodate for curved surfaces [ 7 , 8 , 9 ]. Systems with a limited number of channels tend to rely on external supports to guarantee proper probe attachment, such as bandages or elastic/adhesive straps tightened around the probe.…”