Modified beer-lambert law for blood flow

Wesley B. Baker, Ashwin B. Parthasarathy, David R. Busch, Rickson C. Mesquita, Joel H. Greenberg, A. G. Yodh

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The modified Beer-Lambert law is among the most widely used approaches for analysis of near-infrared spectroscopy (NIRS) reflectance signals for measurements of tissue blood volume and oxygenation. Briefly, the modified Beer-Lambert paradigm is a scheme to derive changes in tissue optical properties based on continuous-wave (CW) diffuse optical intensity measurements. In its simplest form, the scheme relates differential changes in light transmission (in any geometry) to differential changes in tissue absorption. Here we extend this paradigm to the measurement of tissue blood flow by diffuse correlation spectroscopy (DCS). In the new approach, differential changes of the intensity temporal auto-correlation function at a single delay-time are related to differential changes in blood flow. The key theoretical results for measurement of blood flow changes in any tissue geometry are derived, and we demonstrate the new method to monitor cerebral blood flow in a pig under conditions wherein the semi-infinite geometry approximation is fairly good. Specifically, the drug dinitrophenol was injected in the pig to induce a gradual 200% increase in cerebral blood flow, as measured with MRI velocity flow mapping and by DCS. The modified Beer-Lambert law for flow accurately recovered these flow changes using only a single delay-time in the intensity auto-correlation function curve. The scheme offers increased DCS measurement speed of blood flow. Further, the same techniques using the modified Beer-Lambert law to filter out superficial tissue effects in NIRS measurements of deep tissues can be applied to the DCS modified Beer-Lambert law for blood flow monitoring of deep tissues.

Original languageEnglish (US)
Title of host publicationOptical Tomography and Spectroscopy of Tissue XI
EditorsRobert R. Alfano, Eva M. Sevick-Muraca, Bruce J. Tromberg, Arjun G. Yodh
PublisherSPIE
ISBN (Electronic)9781628414097
DOIs
Publication statusPublished - Jan 1 2015
Externally publishedYes
EventOptical Tomography and Spectroscopy of Tissue XI - San Francisco, United States
Duration: Feb 9 2015Feb 11 2015

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
Volume9319
ISSN (Print)1605-7422

Conference

ConferenceOptical Tomography and Spectroscopy of Tissue XI
CountryUnited States
CitySan Francisco
Period2/9/152/11/15

    Fingerprint

Keywords

  • Optical blood flow monitoring
  • speckle
  • Spectroscopy

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Atomic and Molecular Physics, and Optics
  • Radiology Nuclear Medicine and imaging

Cite this

Baker, W. B., Parthasarathy, A. B., Busch, D. R., Mesquita, R. C., Greenberg, J. H., & Yodh, A. G. (2015). Modified beer-lambert law for blood flow. In R. R. Alfano, E. M. Sevick-Muraca, B. J. Tromberg, & A. G. Yodh (Eds.), Optical Tomography and Spectroscopy of Tissue XI [931919] (Progress in Biomedical Optics and Imaging - Proceedings of SPIE; Vol. 9319). SPIE. https://doi.org/10.1117/12.2080185