Quantitative measurement of muscle hemoglobin oxygenation using near-infrared spectroscopy with correction for the influence of a subcutaneous fat layer

Abstract

The inhomogeneity of tissue structure greatly affects the sensitivity of tissue oxygenation measurement by reflectance near-infrared spectroscopy. In this study, we investigated the influence of a fat layer on muscle oxygenation measurement by in vivo tests and Monte Carlo simulation, and we propose a method for correcting the influence. In the simulation, a three-dimensional model consisting of the epidermis, dermis, fat, and muscle layers was used. In in vivo tests, measurement sensitivity was examined by measuring oxygen consumption of the forearm muscle and the peak-to-peak variation of oxygenation in periodic exercise tests on the vastus lateralis using a newly developed multisensor type of tissue oximeter. Fat layer thickness was also measured by ultrasonography. The correction curve of measurement sensitivity against fat layer thickness was obtained from the results of simulation and in vivo tests. The values of corrected oxygen consumption were almost the same and had less variation between individuals (0.13±0.02 ml 100 g−1 min−1) than did the uncorrected values (0.08±0.04 ml 100 g−1 min−1).

Brown adipose tissue density measured by near-infrared time-resolved spectroscopy in Japanese, across a wide age range

“…This corresponds to an attenuation of the NIR signal by <10% of the assumed 0-mm fat layer thickness. 32 After the elimination of the effect of confounder factors, using stepwise multiple regressions, the relationship between BAT-d and BMI, %BF, and VFA was obtained.…”

Relating pulmonary oxygen uptake to muscle oxygen consumption at exercise onset: in vivo and in silico studies

“…Other potential sources of uncertainty in the measurements with NIRS are the unknown region investigated that can be only estimated, interference of adipose tissue thickness (Niwayama et al 2000), and relative contributions of Hb and Mb (Mancini et al 1994;Tran et al 1999). Most studies focus on Hb changes, since it has been reported that intracellular Mb accounts for less than 10% of the total NIRS signal (Grassi et al 2003).…”

Knee extensor muscle oxygen consumption in relation to muscle activation

“…2) ), which is standard procedure . By expressing mVO 2 in this manner, potential diVerences in subcutaneous fat between muscles, which greatly aVect NIRS measurement sensitivity (Niwayama et al 2000;van Beekvelt et al 2001), are accounted for. Maximal deoxygenation is deWned as the absolute diVerence in [O 2 Hb] (and [HHb]) when virtually all O 2 Hb is converted into HHb.…”