Abstract
Abstract: :
Purpose: To evaluate the potential of 80 MHz ultrasound for the imaging of retinal layers and detection of hereditary retinal degeneration. Methods: The study included RCS rats with retinal degeneration at different stages of the disease development and their corresponding non-dystrophic controls. The animals were sacrificed at different post-natal stages (25, 35, 45 and 55 days). The dystrophic RCS eyes (n=20) and the non-dystrophic controls (n=20) were enucleated, fixed, and examined using an 80 MHz three-dimensional (3-D) ultrasound bio-microscope (25 microns axial resolution). A series of parallel B-scan-images of a region close to the optic nerve was acquired, through the sclera from outside the intact globe. Ultrasound images allowed analysis of retinal structure and measurement of retinal thickness. Ultrasound findings were compared to histology. Results: Ultrasound images of both control and pathological eyes obtained at different post-natal stages showed the entire retina thickness and allowed the visualization of different layers within the tissue. Control retina displayed four layers and no variation in thickness with age. The retina thickness of RCS dystrophic eyes decreased over time. At 55 days of age, images of RCS retina displayed three layers and loss of the deep layer, identified previously as the outer nuclear and segments layers of the retina. Ultrasound observations were consistent with retinal histology. Conclusions: High resolution ultrasonography allows detection of local loss of retinal layer in a model of rat degenerative disease. This relevant technique has potential to monitor retinal changes during the time course of degenerative pathologies. It may be very helpful for quantitative evaluation of the effects of genic and pharmacologic therapies in small animals.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, S • degenerations/dystrophies • animal model