Hybrid DCS-DRS System for Deep Tissue Blood Flow and Oxygenation
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Solution Overview
Problem
Current methods for measuring blood flow in tissues, such as diffuse correlation spectroscopy (DCS), are limited by their inability to characterize media with spatially varying dynamic properties and lack of continuous measurement capabilities during exercise, especially in smaller vessels and deep tissues.
Innovation Solution
A hybrid system combining diffuse correlation spectroscopy (DCS) and diffuse reflection spectroscopy (DRS) measures blood flow rate, hemodynamics, and oxygenation characteristics in deep tissues by monitoring light fluctuations and transmission through tissues, allowing for simultaneous measurement of blood cell movement and velocity, enabling continuous monitoring during varying exercise intensities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If diffuse correlation spectroscopy is used to measure blood flow in deep tissues, then non-invasive continuous measurement is achieved, but spatial resolution and ability to characterize spatially varying properties deteriorates
Solution Approach 1:
The patent divides the measurement process into multiple wavelength channels (e.g., 785nm for flow, 690nm/830nm for oxygenation) and multiple source-detector separation distances. Each wavelength and separation distance provides information about different tissue depths and vascular beds, effectively segmenting the measurement space to achieve both continuous monitoring and spatial discrimination.
Solution Approach 2:
The patent adds the wavelength dimension to the traditional temporal correlation measurement. By measuring diffuse correlation at multiple wavelengths and combining with spectroscopic oxygenation measurements, the system transforms a one-dimensional temporal measurement into a multi-dimensional measurement space that simultaneously provides flow, oxygenation, and depth-resolved information.
2Measurement precision
If MRI is used for blood flow measurement, then spatial and temporal resolution is improved, but cost and mobility deteriorates
Solution Approach 1:
The patent replaces the complex mechanical and magnetic field-based MRI system with a simpler optical system using diffuse correlation spectroscopy. The optical system uses light sources and photodetectors to measure blood flow through temporal correlation of intensity fluctuations, eliminating the need for expensive MRI scanners while achieving comparable functional measurement capabilities through a portable device.
3Ease of operation
If conventional Doppler techniques are used, then measurement of large vessels is achieved, but sensitivity to small vessels deteriorates
Solution Approach 1:
The patent changes the measurement parameter from velocity (Doppler) to temporal correlation of intensity fluctuations. This parameter change enables sensitivity to the slower, more random motion of red blood cells in small vessels, whereas conventional Doppler requires higher velocities to generate detectable frequency shifts. The optical scattering parameter also changes from coherent Doppler to incoherent diffuse correlation, enhancing small vessel detection.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach provides non-invasive, continuous measurement of blood flow and oxygenation in deep tissues with high temporal resolution, facilitating improved diagnosis and treatment assessment for conditions like peripheral arterial disease and brain activation, while being more accurate and cost-effective than MRI.
Implementation Method 1
measuring the temporal intensity fluctuations of photon streams that have been scattered within the medium. The medium's properties, for example blood flow rate, are then determined using measured temporal correlation functions of the diffuse light
Implementation Method 2
Multiple scattering from the blood occurred, resulting for example, in a Doppler broadening of the indirect laser linewidth
Implementation Method 3
measuring the temporal intensity fluctuations of photon streams that have been scattered within the medium
Implementation Method 4
The medium's properties, for example blood flow rate, are then determined using measured temporal correlation functions of the diffuse light
Data Source
AI summary
An embodiment of the invention includes a device, system and method for determining the characteristics of deep tissue. The novel method includes measuring blood flow rate and oxygenation characteristics of the tissue, and determining oxygen metabolism of the tissue as a function of the measure blood flow rate and measure oxygenation. The blood flow rate characteristics are measured as a function of light fluctuations caused by the tissue, while the oxygenation characteristics are measured as a function of transmission of light through the tissue with respect to the wavelength of light. The tissue may be layered tissue, for example, a portion of a brain. The tissue characteristics may be measured during times of varying levels of exercise intensity.