Blood Perfusion Imaging With Optical Depth Source Estimation
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Solution Overview
Problem
Current perfusion imaging systems, such as PPGI and SCI, suffer from ambiguity due to the unknown source of the signal depth, leading to challenges in interpreting false color images, which limits their commercial success and clinical utility.
Innovation Solution
A device and method that utilize optical depth indices (ODIs) to determine the depth of blood flow signals, combining widefield and radial imaging to create accurate, depth-corrected amplitude image maps, resolving the ambiguity by estimating the source depth of PPG and SC signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If PPGI or SCI imaging techniques are used to capture blood perfusion, then perfusion information can be obtained, but the source depth of the signal remains unknown creating ambiguity in interpretation
Solution Approach 1:
The imaging system divides the skin region into multiple depth layers by using multiple illumination sources at different positions and angles. This segmentation allows the system to separately capture signals from different depth levels, resolving the ambiguity of unknown source depth while maintaining comprehensive perfusion information.
Solution Approach 2:
The patent introduces a new spatial dimension by positioning multiple illumination sources at different radial distances from the skin surface. This creates a three-dimensional imaging approach where signals can be differentiated by their origin depth, transforming the traditional two-dimensional surface imaging into a depth-resolved three-dimensional representation.
2Measurement precision
If multiple illumination sources at different positions are used to determine source depth, then depth information is obtained, but device complexity increases
Solution Approach 1:
The multiple illumination sources serve dual functions: they illuminate the skin region for perfusion imaging and simultaneously provide depth information through their radial positioning. This multi-functionality allows the system to achieve depth resolution without adding separate depth-measurement components, thereby limiting the increase in device complexity.
Solution Approach 2:
The patent merges the illumination function with the depth-probing function by using the same set of radially arranged light sources for both purposes. The illumination sources are positioned at different radial distances to create depth-selective illumination patterns, combining structural illumination with depth encoding in a single integrated system.
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 higher-quality imaging of blood perfusion by providing accurate, depth-resolved images that distinguish between different depths of blood motion, improving interpretation and clinical utility.
Implementation Method 1
obtain data streams derived from detected electromagnetic radiation transmitted through or reflected from the skin region
Implementation Method 2
Due to Beer's law of attenuation, the signal dependency on source depth is exponential
Data Source
AI summary
The present invention relates to a device (100), systems (500, 500′, 500″) and a method for providing imaging of one or more aspects of blood perfusion induced by cardiac induced blood motion in a skin region (12) of a subject. Current perfusion imaging systems use either photoplethysmography (PPG) or speckle contrast (SC), but a problem of both techniques is that considerable ambiguity exists because the source of the signal (volume pulsatility in PPG or blood flow in SC) is unknown. The present invention is based on the idea of combining two different types of measurement, namely widefield imaging and radial imaging, in order to estimate the source depth (20) of the signal to provide more accurate PPG imaging and SC imaging.