Retinal LSCI Optics With Polarization Gating for Hemodynamic Mapping
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Solution Overview
Problem
Current retinal imaging modalities, such as OCT and OCT-angiography, are limited in their ability to quantify physiological changes in retinal hemodynamics and vascular function, particularly in diseases like diabetic retinopathy and age-related macular degeneration, and lack strong correlations between anatomical and functional biomarkers, necessitating the development of a non-invasive imaging technique that can provide wide-field maps of blood flow and quantify early functional changes.
Innovation Solution
A laser-speckle contrast imaging (LSCI) system is designed with a customized optical illumination system and light-collecting system, utilizing a set of optical apertures defined by an optical fiber component, to generate high-speed, non-contact, and wide-field maps of retinal hemodynamics, capable of quantifying blood flow and cardiac parameters without specular reflections, and allowing for multiplexed illumination with varying degrees of coherence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional imaging modalities (OCT, OCT-angiography) are used to image retinal structures, then anatomical resolution is improved, but the ability to quantify physiological changes in retinal hemodynamics deteriorates
Solution Approach 1:
The patent segments the imaging function into two distinct modalities: OCT for anatomical imaging and LSCI for functional hemodynamic imaging. This segmentation allows each modality to be optimized for its specific purpose - OCT provides high-resolution anatomical structure while LSCI provides quantitative blood flow information, thereby resolving the contradiction between anatomical resolution and physiological information capture
Solution Approach 2:
The patent combines multiple imaging modalities (OCT and LSCI) into a single integrated system that can perform both anatomical imaging and functional hemodynamic measurement. This multi-functionality allows the system to simultaneously capture structural and physiological information, eliminating the trade-off between anatomical resolution and physiological information
2Measurement precision
If Doppler-OCT is used for quantitative velocimetry, then blood flow measurement capability is improved, but sensitivity to vessel orientation complicates clinical use
Solution Approach 1:
The patent replaces the Doppler-OCT method with LSCI for blood flow measurement. LSCI uses speckle contrast analysis of scattered light rather than Doppler frequency shifts, making it insensitive to vessel orientation relative to the illumination source. This substitution maintains quantitative blood flow measurement capability while dramatically improving clinical usability by eliminating the orientation sensitivity problem
3Difficulty of detecting and measuring
If existing imaging modalities are used for vascular assessment, then qualitative assessment capability is improved, but correlation between anatomy and function deteriorates
Solution Approach 1:
The patent merges anatomical imaging (OCT) with functional hemodynamic imaging (LSCI) into a single integrated system. This merging allows simultaneous acquisition of structural and functional data from the same retinal region, enabling direct correlation between anatomical features and physiological function, thereby resolving the contradiction between assessment capability and biomarker correlation
4Area of stationary object
If LSCI is used for wide-field blood flow mapping, then field-of-view is improved, but measurement of early functional changes in retinal hemodynamics deteriorates
Solution Approach 1:
The patent optimizes LSCI parameters including using a high numerical aperture objective lens (0.85), specific laser wavelengths (785 nm or 808 nm), and controlled exposure times to achieve both wide-field coverage and high measurement precision. By carefully adjusting these parameters, the system maintains quantitative accuracy while expanding the field-of-view for comprehensive retinal hemodynamic assessment
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
The LSCI system effectively measures retinal hemodynamics and cardiac function with high spatial and temporal resolution, enabling early detection of anatomical and physiological changes in retinal vascular diseases, potentially improving disease management and identifying novel biomarkers.
Implementation Method 1
an optical illumination system having an optical axis and including a group of lenses and a set of optical apertures dimensioned to deliver light to the group of lenses in transmission of the light through at least one of the aperture(s)
Implementation Method 2
transmitting a portion of the first illuminating light from a retinal surface towards an optical lens of an optical light-collecting system through a designated area of the target surface
Implementation Method 3
laser speckle contrast imaging (LSCI) is a promising, but underutilized, non-invasive, and non-contact imaging technique capable of generating wide-field maps of blood flow
Implementation Method 4
illuminating a rigid surface (e.g., a retinal blood vessel) with light generated by a coherent light source results in the formation of a random 'speckle pattern'
Data Source
Figure 1A
Figure 1B~1C
Figure 2A~2C
AI summary
Laser-Speckle Contrast imaging apparatus configured to assess and quantify motion associated with an object and, in a specific case of an eye - retinal vascular anatomy and hemodynamics and generate substantially contrast-free maps of retinal blood flow over a wide field-of-view at up to 590 fps and under short exposure durations (> 50µs), is applicable for diagnosis, study, and management of neurodegenerative conditions (i.e. mild cognitive impairment and Alzheimer's disease) and systemic cardiovascular diseases (i.e. athero- and arteriosclerosis, coronary artery occlusion, and hypertension). The apparatus employs a) a set of apertures substantially blocking light, delivered from a source of light to an illumination arm of the apparatus, from impinging onto an axial point of the front surface of the lens of the illumination arm, and b) polarization gating between the illumination and light-collecting arms of the apparatus. In one implementation, the apparatus is configured to allow for irradiation of the object with an optical field a degree of coherence and/or spectral content of which are varied delivered through the same optical train including the set of apertures.