Retinal Laser Speckle Imaging with Polarization Gating
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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 AMD, 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 vascular dysfunction.
Innovation Solution
A laser-speckle contrast imaging (LSCI) system with a customized optical design using a set of optical apertures defined by an optical fiber component, configured to deliver light with varying degrees of coherence and polarization, allowing for high spatial and temporal resolution imaging of retinal hemodynamics without contacting the cornea, and capable of quantifying blood flow and cardiac parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If OCT and OCT-angiography are used for retinal imaging, then anatomical resolution is improved, but the ability to quantify physiological changes in retinal hemodynamics deteriorates
Solution Approach 1:
The patent combines structural imaging (OCT) with functional imaging (LSCI) into a single integrated system. The OCT module provides high-resolution anatomical information while the LSCI module simultaneously captures blood flow dynamics, merging both capabilities to eliminate the trade-off between anatomical resolution and physiological information.
Solution Approach 2:
The imaging system is designed to perform multiple functions: structural imaging via OCT, blood flow quantification via LSCI, and co-registration of both modalities. This multi-functional approach allows simultaneous acquisition of anatomical and physiological data from the same retinal region, providing comprehensive diagnostic 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 uses LSCI as an intermediary technique that provides orientation-independent blood flow measurements. Unlike Doppler-OCT which requires specific vessel orientations relative to the illumination source, LSCI captures speckle patterns from scattered light that reflect blood flow regardless of vessel angle, serving as a complementary method that eliminates orientation sensitivity issues.
3Measurement precision
If existing imaging modalities are used, then anatomical assessment is improved, but correlation between anatomical and functional biomarkers deteriorates
Solution Approach 1:
The patent adds a functional dimension to traditional anatomical imaging by integrating LSCI blood flow measurements with OCT structural data. This multi-dimensional approach correlates anatomical features (from OCT) with functional parameters (blood flow from LSCI) in the same spatial location, enabling comprehensive assessment that links structure and function.
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 functions with high precision, enabling early detection of vascular changes and providing quantitative biomarkers for retinal diseases, potentially improving disease management and treatment efficacy.
Implementation Method 1
In LSCI, 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', where the intensity of each pixel results from the coherent addition of backscattered light with different optical path lengths
Implementation Method 2
the set of optical apertures may be defined by an optical fiber component having at least one output optical fiber facet facing the group of lenses
Data Source
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 (>50 μs), 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.