Retinal Speckle Imaging Optics for Quantitative Blood Flow Mapping
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Solution Overview
Problem
Current retinal imaging modalities, such as OCT and OCT-angiography, are limited in their ability to quantitatively assess vascular health and function, particularly in diseases with vascular etiology like diabetic retinopathy and age-related macular degeneration, and lack correlation between anatomical and functional changes, necessitating the development of a non-invasive imaging technique that can quantify early physiological variations.
Innovation Solution
A laser-speckle contrast imaging (LSCI) system with a customized optical design that includes a set of optical apertures and an optical fiber component, configured to provide non-contact, wide-field, high-resolution maps of retinal hemodynamics, capable of quantifying blood flow and vascular function without specular reflections, and allowing variable coherence illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional imaging modalities (OCT, OCT-angiography) are used, then anatomical resolution is improved, but quantitative assessment of vascular function deteriorates
Solution Approach 1:
The system segments the imaging function into two distinct modalities: OCT for anatomical imaging and LSCI for functional blood flow imaging. This allows each modality to optimize its performance independently, with OCT providing high-resolution anatomical structures and LSCI providing quantitative functional data, thereby resolving the contradiction between anatomical resolution and functional assessment capability
Solution Approach 2:
The patent merges OCT and LSCI into a single integrated imaging system that combines the strengths of both modalities. The OCT component provides detailed anatomical imaging while the LSCI component simultaneously captures dynamic blood flow information, enabling both high anatomical resolution and quantitative functional assessment to be achieved together rather than traded off against each other
2Measurement precision
If Doppler-OCT is used for quantitative velocimetry, then blood flow measurement capability is improved, but sensitivity to vessel orientation worsens
Solution Approach 1:
The patent introduces LSCI as an intermediary technique that measures blood flow based on speckle contrast analysis rather than Doppler frequency shifts. This intermediary approach eliminates the orientation sensitivity problem inherent in Doppler-OCT, as LSCI measures the temporal fluctuations of speckle patterns caused by moving red blood cells, providing quantitative blood flow measurements that are independent of vessel orientation relative to the illumination source
3Manufacturing precision
If existing imaging modalities are used, then anatomical visualization is improved, but correlation with functional changes deteriorates
Solution Approach 1:
The integrated system merges anatomical imaging (OCT) with functional imaging (LSCI) into a single coherent system. This allows direct correlation between anatomical structures visualized by OCT and functional blood flow parameters measured by LSCI at the same location and time, eliminating the loss of functional information that occurs when using separate imaging modalities. The system simultaneously captures both anatomical and functional data, enabling comprehensive correlation between 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 early functional changes in retinal hemodynamics, enabling robust diagnostic tools for retinal vascular diseases, characterizing anatomical and physiological dysfunction, and providing quantitative assessments of blood flow and cardiac parameters.
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 such light through at least of these aperture(s)
Implementation Method 2
laser speckle contrast imaging (LSCI) is a promising, but under-utilized, non-invasive, and non-contact imaging technique capable of generating wide-field maps of blood flow
Data Source
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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.