Ratiometric Fluorescence Imaging for Low-Contrast Lesion Detection
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Solution Overview
Problem
Current autofluorescence endoscopy techniques struggle to effectively enhance the image contrast of low-contrast lesions, such as flat neoplasms, during colonoscopy, leading to missed detections, especially under time constraints and without the use of exogenous chemicals.
Innovation Solution
The use of ratiometric fluorescence imaging systems that selectively target specific autofluorescence signals from native fluorophores like tryptophan, FAD, NADH, and collagen, providing enhanced contrast through the computation of synthetic formulaic images using multiple excitation beams and combining fluorescence and reflectance data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional autofluorescence endoscopy is used, then the examination can be performed without exogenous chemicals, but the image contrast of low-contrast lesions is insufficient leading to missed detections
Solution Approach 1:
The patent segments the autofluorescence signal by using multiple excitation wavelengths to selectively excite different native fluorophores (tryptophan, FAD, NADH, collagen) at different depths and locations within the tissue. This segmentation of the fluorescence signal by wavelength and source enables differentiation of lesion types and improves image contrast without requiring exogenous chemicals
Solution Approach 2:
The system changes the excitation wavelength parameter to selectively target different fluorophores. By varying the excitation wavelength (e.g., 280 nm for tryptophan, 370 nm for collagen, 440 nm for FAD), the system optimizes the autofluorescence signal from specific tissue components, thereby improving lesion detection contrast while maintaining the advantage of using no exogenous agents
2Reliability
If chromoendoscopy with indigo carmine is used, then the detection of flat neoplasms is improved, but the examination time increases significantly
Solution Approach 1:
The system uses endogenous fluorophores naturally present in the tissue (tryptophan, FAD, NADH, collagen) as the contrast agents, eliminating the need for exogenous dyes like indigo carmine. The tissue itself provides the fluorescent signal through its native biochemical components, thereby improving detection accuracy without adding the time required for dye application and waiting periods
Solution Approach 2:
The system performs spectral unmixing and computational processing of autofluorescence signals in real-time during the examination, preparing the enhanced contrast images as the procedure progresses. This preliminary computational action enables immediate lesion identification without requiring post-examination processing or additional time-consuming steps
3Measurement precision
If time-resolved autofluorescence imaging is used, then the confounding factors for intensity measurements are avoided, but the instrumentation complexity and acquisition time increase
Solution Approach 1:
The patent replaces complex time-resolved measurement instrumentation with a simpler spectral approach using multiple excitation wavelengths. Instead of requiring time-gated detectors and complex temporal resolution systems, the invention uses spectral unmixing of autofluorescence signals excited at different wavelengths to achieve precise tissue characterization with simpler, more clinically feasible equipment
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 significantly improves the detection of flat and serrated lesions by providing high-contrast images of neoplastic tissues without the need for dyes or labels, enhancing the detection rate and providing well-defined lesion borders in real-time.
Implementation Method 1
Fluorescence from selected native fluorophores (tryptophan, FAD, NADH and collagen) is detected following illumination with selected wavelengths
Implementation Method 2
Reflectance and autofluorescence measurements are performed at multiple wavelengths
Data Source
AI summary
Methods for reliable identification of low-contrast lesions within a tissue of a subject comprise delivering an excitation signal to the tissue, wherein the excitation signal is selected to stimulate tissue to produce autofluorescence and/or reflectance. The autofluorescence and/or reflectance is detected, and ratiometric images are produced based on the autofluorescence and/or reflectance images. An imaging system is provided which is configured to carry out such methods, irradiating tissue at a various possible excitation wavelengths, such as UV excitation wavelengths below 300 nm, to elicit fluorescence from specific native fluorophores.