Abstract
Purpose: :
Non-invasive imaging technologies for measuring rat and mouse retinal structure and physiology at the micron level could be useful tools for ocular biomedical research. Spectral / Fourier domain OCT enables ultrahigh speed imaging, offering a promising technique for rat and mouse retinal imaging. Ultrahigh speed spectral / Fourier domain OCT enables novel protocols which can be used for measuring rodent retinal structure and retinal blood flow in vivo.
Methods: :
An ultrahigh speed spectral / Fourier domain OCT prototype instrument has been developed for small animal imaging using new high speed CMOS imaging technology. This technology achieves imaging speeds over 100,000 axial scans per second with axial image resolutions of ~3 µm. A microscope delivery system was developed for focusing and scanning the OCT beam in the animal eye. Three dimensional OCT (3D-OCT) data sets of the rodent retina were acquired. Projection OCT fundus images were created from axial summation of 3D-OCT data. Doppler OCT analysis of blood flow in the rodent retina was performed.
Results: :
Ultrahigh speed imaging enables high pixel density 3D-OCT data with minimal eye motion artifacts. Residual motion artifacts can be reduced or eliminated using image processing methods. At such high speeds, the OCT fundus images offer more precise registration of individual OCT images to retinal fundus features. Projection OCT fundus images of normal rodent retina show anatomic features such as the nerve fiber layer, retinal capillary networks, and choroidal vasculature. Doppler OCT provides measurements of blood flow in retinal blood vessels.
Conclusions: :
Ultrahigh speed imaging of the rodent retina was demonstrated at speeds over 100,000 axial scans per second using spectral / Fourier domain OCT. 3D-OCT data sets obtained at high speeds show reduced motion artifacts. Projection OCT fundus imaging enables visualization of fine retinal features. Doppler OCT provides non-invasive measurements of retinal blood flow in vivo and may benefit studies of diseases such as glaucoma and diabetic retinopathy. Therefore, ultrahigh speed spectral / Fourier domain OCT is a promising tool for monitoring disease progression in rat and mouse models to characterize ocular disease pathogenesis and response to treatment.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • retina • blood supply