Oximetry of Retinal Microvasculature in Rodent Eyes with Multi-modal Adaptive Optics Small-animal Imager

Project Summary AbstractPhysical Sciences IncPSIin collaboration with Joslin Diabetes CenterJDCproposes to develop a non invasive high resolution retinal oximetry platform that is able to monitor in vivo retinal oxygen saturationSpOin the rodent eye down to the capillary levelCapillary level assessment is needed to study the early onset of diseaseThis oximetry imaging feature will be built on an existing PSIandapos s Multi modal Adaptive Optics Small animal ImagerMAOSIwhich allows high resolutionandltm transverse resolutionandltm axial resolutioninvestigation of retinal microvasculatureSimultaneousco scanning adaptive optics scanning laser ophthalmoscopyoptical coherent tomographyAOSLO AOOCTrasters will provide significant benefits for image guidancecross modal registration and averagingWith proper management of light safety levels set by ANSI Zwith special consideration of rodent eyesandaposgeometrythe proposed project will take advantage of the high molar extinction coefficient of oxy hemoglobin and deoxyhemoglobin within the blue region of the light spectrum to enhance SpOdetection sensitivityIn additionthe project will incorporate a state of the art split detector AOSLO imaging modality with custom designed multi aperture fibers that is ideally matched with rodent eye numerical aperture to efficiently collect multiply scattered photons through vesselsrather than reflection from vesselallowing the measurement of true light transmittance from bloodAn intuitive graphic user interface will be designed and developed to robustly control all the imaging subsystems and provide image post processing tools for oximetry analysisA temperature controlled holder will keep the animal body temperature constant and minimize cornea and lens opacificationsAfter fully constructed and testedthe instrument will be moved to JDC for oximetry measurement on normal and diabetic animalsBased on the Phase I results and conclusionsa secondgeneration upgraded oximetry MAOSI system will be developed in Phase II to enable oximetry on different animal species strains diseasesproviding an important cutting edge metabolic imaging tool for research institutes and pharmaceutical companies Project NarrativeThe main focus of the project is to build a blue light retinal oximetry imaging function on to PSIandapos s Multimodal Adaptive Optics Small animal ImagerThe added oximetry module will enable high resolutionD characterization of retinal metabolic activity down to the microvasculature levelThis novel feature will allow academic researchers and pharmaceutical companies to investigate early changes in oxygen saturation level due to retinal vascular diseases from diverse etiologiessuch as diabetes