Determination of a Quantitative Algorithm for the Measurement of Muscle Oxygenation Using CW Near-Infrared Spectroscopy Mean Optical Pathlength Without the Influence of Adipose Tissue

Abstract

Near-infrared spectroscopy (NIRS) is a useful technique for noninvasive measurement of oxygenation of the brain and muscle. However, no accurate, quantitative algorithms for continuous wave NIRS (CW-NIRS) have yet been presented dute to the following two problems. The first is that inhomogeneous tissue structure greatly affects measurement sensitivity. We previously reported on the influence of a fat layer on muscle oxygenation measurement and proposed a method for correcting the sensitivity. The second problem is that almost all algorithms for CW-NIRS have been experimentally determined, although an algorithm can be theoretically determined on the basis of diffusion theory if the mean optical pathlength in muscle in an in vivo state is known. In this study, we derived basic equations for a CW-NIRS algorithms based on diffusion theory, and we determined linear and nonlinear algorithms from mean optical pathlengths and validated them by results obtained from phantom experiments. For the determination of pathlength, the absorption and scattering coefficients of the muscle must be obtained by taking into account the influence of a fat layer. Laser pulses of 752 and 871 nm were applied to the forearms of subjects, and the temporal point spread function (TPSF) was obtained by using a streak camera. The absorption and scattering coefficients of the muscle were determined by fitting the measured TPSF with that obtained by a Monte Carlo model consisting of skin, fat and muscle layers. From these coefficients, the mean optical pathlengths at two wavelengths were obtained and the algorithms were determined.

Open PDF

Document Details

Document Type
Technical Report
Publication Date
Jul 01, 2000
Accession Number
ADP011221

Entities

People

  • Jun Shao
  • Katsuynki Yamamoto
  • Ling Lin
  • Masatsugu Niwayama
  • Nobuki Kudo

Organizations

  • Hokkaido University

Tags

Communities of Interest

  • Biomedical

DTIC Thesaurus Topics

  • Abdomen
  • Absorption Coefficients
  • Adipose Tissue
  • Cameras
  • Coefficients
  • Detectors
  • Equations
  • Hemoglobin
  • Infrared Spectroscopy
  • Light Sources
  • Monte Carlo Method
  • Optical Detection
  • Optical Properties
  • Oxygenation
  • Scattering
  • Simulations
  • Streak Cameras

Readers

  • Calculus or Mathematical Analysis
  • Optical Physics and Photonics.
  • Trauma Surgery or Emergency Medicine.

Technology Areas

  • Directed Energy
  • Directed Energy - Lasers