Laser Speckle Imaging Vasculature Mapping
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Solution Overview
Problem
Current methods fail to effectively detect flow properties in biological tissues using coherent illumination, particularly in scattering environments, as they struggle to accurately interpret time-varying patterns of constructive and destructive interference caused by moving scatterers like blood cells.
Innovation Solution
A system comprising a light source emitting coherent illumination, an imager with light-sensitive elements to capture time-varying patterns, and a controller to analyze these patterns and determine flow properties within biological tissues, allowing for the mapping of vasculature and detection of fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If coherent illumination is used to detect flow properties in biological tissue, then measurement capability is improved, but the complexity of interpreting time-varying interference patterns increases
Solution Approach 1:
The patent introduces speckle patterns as an intermediary phenomenon that mediates between the coherent light illumination and the flow property measurement. The moving scatterers (blood cells) modulate the coherent light to produce time-varying speckle patterns, which serve as a readable signal that encodes flow information. This intermediary transformation makes the invisible flow properties detectable through optical means.
Solution Approach 2:
The patent replaces direct mechanical or electrical flow measurement methods with an optical-based speckle analysis system. Instead of using mechanical probes or electrical sensors in the tissue, the system uses coherent light illumination and optical detection of speckle pattern variations to infer flow properties, thereby avoiding mechanical intrusion and enabling non-contact measurement.
2Loss of information
If speckle patterns are used to map vasculature, then imaging capability is improved, but the difficulty of detecting and measuring increases
Solution Approach 1:
The patent applies preliminary spatial filtering to the speckle patterns before full analysis. By using spatial filters to preprocess the speckle patterns and extract relevant frequency components, the system prepares the data in advance for more accurate vasculature mapping. This preliminary processing step reduces the complexity of subsequent measurements by pre-organizing the information.
Solution Approach 2:
The patent utilizes the periodic nature of speckle pattern variations caused by rhythmic blood flow. By analyzing the temporal frequencies of speckle intensity variations at different spatial locations, the system can identify periodic flow patterns and map vasculature based on these rhythmic modulations, converting a complex continuous signal into analyzable periodic components.
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 precise determination of flow properties and vasculature mapping within biological tissues, facilitating surgical interventions by providing real-time data on fluid flow and tissue structures.
Implementation Method 1
Illumination of a scattering environment (e.g., an environment containing rough surfaces or other scattering objects or features) by a source of coherent, monochromatic light (e.g., a laser) can result in light emitted (i.e., reflected, refracted, diffracted, or otherwise scattered) from the environment forming a speckle pattern
Implementation Method 2
constructive and destructive interference between coherent, monochromatic light that takes different paths through the scattering environment due to scattering by features of the environment
Data Source
AI summary
Systems are provided for detecting the flow of blood or other fluids in biological tissue by illuminating the biological tissue with a coherent light source and detecting time-varying patterns of constructive and destructive interference in light received from portions of the biological tissue by an imager. The movement of blood cells and other light-scattering elements in the biological tissue causes transient, short-duration changes in light emitted from portions of the biological tissue proximate to the moving blood cells or other scatterers. High-frequency sampling or other high-bandwidth processing of light intensities detected by an imager could be used to determine the flow of blood or other fluids at a plurality of points in the biological tissue, to detect and/or localize a tumor in the biological tissue, to determine the location, pattern, width, or other properties of vasculature in the biological tissue, or to provide information for some other application(s).