Crosstalk and error analysis of fat layer on continuous wave near-infrared spectroscopy measurements

Abstract

Accurate estimation of concentration changes in muscles by continuous wave near-IR spectroscopy for muscle measurements suffers from underestimation and crosstalk problems due to the presence of superficial skin and fat layers. Underestimation error is basically caused by a homogeneous medium assumption in the calculations leading to the partial volume effect. The homogeneous medium assumption and wavelength dependence of mean partial path length in the muscle layer cause the crosstalk. We investigate underestimation errors and crosstalk by Monte Carlo simulations with a three layered (skin-fat-muscle) tissue model for a two-wavelength system where the choice of first wavelength is in the 675- to 775-nm range and the second wavelength is in the 825- to 900-nm range. Means of absolute underestimation errors and crosstalk over the considered wavelength pairs are found to be higher for greater fat thicknesses. Estimation errors of concentration changes for Hb and HbO(2) are calculated to be close for an ischemia type protocol where both Hb and HbO(2) are assumed to have equal magnitude but opposite concentration changes. The minimum estimation errors are found for the 700825- and 725825-nm pairs for this protocol.

Simultaneous measurement of deep tissue blood flow and oxygenation using noncontact diffuse correlation spectroscopy flow-oximeter

“…The ATT influence is another concern with NIRS measurements5354. The penetration depth of NIR light in biological tissues is known to be roughly half of the S-D separation55.…”

Monitoring hemodynamic changes in stroke-affected muscles using near-infrared spectroscopy

“…Table 1 shows the optical properties of the different layers of tissues at 850 nm wavelength that were used in the simulation. 25…”

“…Table 1 shows the optical properties of the different layers of tissues at 850 nm wavelength that were used in the simulation. 25 Figure 1(a) shows the Monte Carlo simulation results for three different source-detector separation distances, 5 mm, 10 mm and 20 mm obtained by simulating the trajectories of 10 8 photons. Based on the results shown in Figure 1(a), as the source-detector separation distance increases, more information from the deeper areas in the tissue can be obtained.…”

Dose Analysis of Photobiomodulation Therapy in Stomatology

“…The anisotropic coefficient ( g ) of angular distribution was used to simulate the light scattering at 660 nm [ 28 , 29 ] and 825 nm [ 30 , 31 ]. The wavelength of 660 nm indicated the most scattering in the epidermis layer of angular distribution by light scattering ( Figure 9 ).…”

“…The optical parameters of μ a and μ s as mentioned in previous studies were used [ 28 , 29 ]. However, the light intensity propagation in the dermis layer was stronger with the 825 m laser than the 660 nm laser (optical parameters of μ a and μ s as mentioned in previous studies were used [ 30 , 31 ]). This result indicates that the NIR light provided higher penetration depth than the red light ( Figure 11 ).…”