Contactless Tissue Viability Assessment Using Polarized Light
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Solution Overview
Problem
Conventional methods for assessing tissue viability in burn wounds, such as Laser Doppler Imaging and Indocyanine green angiography, are invasive, time-consuming, and may not accurately detect necrotic tissue, posing risks of infection and requiring intrusive procedures.
Innovation Solution
A contactless system utilizing polarized light sources and detectors to emit and detect light at specific wavelengths, performing frequency domain analysis to generate a two-dimensional hemodynamic map indicative of tissue viability, allowing for real-time assessment without tissue contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional LDI is used to assess tissue viability, then noninvasive blood flow measurement is achieved, but the risk of wound infection and tissue trauma increases due to direct probe contact
Solution Approach 1:
The patent replaces the mechanical contact-based LDI probe with a contactless optical system using laser light and cameras to measure tissue blood flow. This substitution eliminates physical contact with the wound, removing the source of infection risk and tissue trauma while maintaining the ability to assess tissue viability through optical detection of hemodynamic oscillations
Solution Approach 2:
The patent introduces light as an intermediary medium to transfer information about tissue blood flow without direct contact. By using laser light that penetrates tissue and detecting the Doppler shift in reflected light, the system mediates between the measurement goal and the wound, allowing assessment without harmful contact
2Productivity
If conventional LDI is used to measure blood flow at one spot, then localized perfusion data is obtained, but assessing large burn wounds becomes time-consuming
Solution Approach 1:
The patent segments the large wound area into multiple regions that can be simultaneously imaged by an array of cameras or a single wide-field camera system. This allows parallel measurement of blood flow across multiple spots at once, transforming the sequential point-by-point measurement into a simultaneous area-wide assessment
Solution Approach 2:
The patent transitions from one-dimensional point measurement to two-dimensional area imaging by using optical fields that cover extensive wound surfaces. The system captures spatial distribution of blood flow across the entire wound area, adding the spatial dimension to the measurement and enabling comprehensive assessment of large burns in a single capture
3Object-affected harmful factors
If conventional ICG video-angiography is used to visualize deep dermal vasculature, then greater skin imaging penetration is achieved, but intravascular dye injection is required which carries high risk of adverse reactions
Solution Approach 1:
The patent replaces the chemical-based ICG dye injection method with a contactless optical measurement system using laser light. This substitution eliminates the need for intravascular dye injection, removing the source of adverse reactions while maintaining the ability to visualize and measure deep dermal vasculature through optical detection of blood flow oscillations
Solution Approach 2:
The patent utilizes the body's own spontaneous hemodynamic oscillations as the signal source rather than requiring external dye injection. The system detects natural blood flow variations that occur rhythmically in living tissue, allowing the tissue itself to provide the measurement signal without external intervention
4Measurement precision
If conventional tissue excision procedure is used to determine tissue viability, then visual inspection of capillary bleeding is achieved, but the assessment remains subjective and imprecise
Solution Approach 1:
The patent replaces subjective visual inspection with an automated optical measurement system that objectively quantifies tissue blood flow. The system uses laser light and image processing to detect and measure hemodynamic oscillations, transforming the subjective visual assessment into an objective, quantifiable measurement of tissue viability
Solution Approach 2:
The patent implements real-time feedback by continuously monitoring blood flow oscillations and providing immediate objective data about tissue viability. This feedback loop allows for precise, data-driven decisions about debridement extent, replacing the delayed and subjective visual inspection with continuous objective measurement
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
Enables objective, real-time evaluation of tissue viability and hemodynamic parameters, reducing the risk of infection and improving the accuracy of debridement by providing quantitative metrics for optimal treatment planning.
Implementation Method 1
One or more polarizers each coupled to one or more of the one or more light sources are configured to polarize the light to a polarized state such that the polarized light in the polarized state diffuses into the tissue in the predetermined area at a predetermined depth and the polarized light is maintained in the polarized state at the predetermined depth
Implementation Method 2
One or more detectors each including a detector polarizer coupled thereto are configured to discriminate the light maintained in the polarized state and at the predetermined depth
Implementation Method 3
one or more light sources configured to emit lights at a predetermined wavelength sensitive to hemoglobin concentration associated with spontaneous hemodynamic oscillations at tissue
Data Source
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AI summary
A contactless system for assessing tissue viability and other hemodynamic parameters includes one or more light sources configured to emit lights at a predetermined wavelength sensitive to hemoglobin concentration associated with spontaneous hemodynamic oscillations at tissue in a predetermined area of a human subject. One or more polarizers are each coupled to one or more of the light sources and are configured to polarize the light to a polarized stale such that the polarized light in the polarized state diffuses into the tissue in the predetermined area at a predetermined depth and the polarized light is maintained in the polarized state at the predetermined depth. One or more detectors, each including a detector polarizer coupled thereto are configured to discriminate the light maintained in the polarized state and at the predetermined depth, are configured to generate a plurality of frames of the tissue in the predetermined area at the predetermined depth.