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Theoretical model of blood flow measurement by diffuse correlation spectroscopy
Sava Sakadžic1, David A Boas1, Stefan Carp1
1Massachusetts General Hospital and Harvard Medical School, Optics Division, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, Massachusetts, United States.
Journal of Biomedical Optics
|February 28, 2017
Summary
Diffuse correlation spectroscopy (DCS) quantifies tissue perfusion. New theory explains DCS signal decay as shear-induced red blood cell diffusion, not just blood flow, improving perfusion measurements.
Area of Science:
- Biomedical Optics
- Biophysics
- Medical Imaging
Background:
- Diffuse correlation spectroscopy (DCS) noninvasively measures tissue perfusion using light scattering.
- Existing models often struggle to reconcile DCS data with blood flow dynamics.
- The diffusive nature of DCS signals in tissue requires further theoretical explanation.
Purpose of the Study:
- To provide theoretical support and generalization for the role of shear-induced diffusion in DCS signals.
- To develop a comprehensive theoretical framework for DCS autocorrelation functions.
- To propose methods for incorporating realistic vascular properties into DCS analysis.
Main Methods:
- Derivation of autocorrelation function expressions based on diffusing-wave spectroscopy.
- Inclusion of both diffusive and advective scatterer motion within a photon path model.
- Development of correlation diffusion and correlation transfer equations for arbitrary geometries.
Main Results:
- Theoretical derivations confirm that shear-induced diffusion of red blood cells significantly influences DCS autocorrelation decay.
- A generalized solution for the DCS autocorrelation function in semi-infinite and arbitrary geometries was obtained.
- New equations (correlation diffusion and transfer) were derived for enhanced DCS analysis.
Conclusions:
- Shear-induced diffusion is a critical factor in interpreting DCS measurements of tissue perfusion.
- The derived theoretical framework and equations advance the accuracy and applicability of DCS.
- Proposed methods pave the way for more realistic modeling of vascular morphology and flow in DCS.
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