Date of Award
Master of Science
Electrical and Computer Engr
Assessing vascular structure of the retina is useful for diagnosis and management of pathological conditions of the eye such as glaucoma, diabetic retinopathy, vein occlusion and retinal neo-vascularization. Optical coherence tomography (OCT) is an optical imaging technique based on the principle of low-coherence interferometry and can be used to image various ocular structures non-invasively. Ocular structures such as blood vessels and collagen with high optical absorption and/or scattering significantly attenuate OCT light propagation and thus, cast shadows below these highly attenuating locations in OCT a-scans. An improved attenuation compensation procedure is presented to minimize shadows and resolve tissue structure by solving an integral equation with exponential non-linearity that govern OCT light transport in a tissue. Frangi filter was used to extract retinal blood vessel network from 2D photographs and 3D OCT scans of the retina. The location and orientation of retinal blood vessels were identified using eigen analysis of the Hessian matrix at each retinal location. Vessels of varying diameters were identified by conducting eigen analysis at multiple scales using scale-space theory. Further, a 3-D geometrical model of the vessel network was extracted from the scale-space analysis. Our methodology was evaluated using 2D photographs of human subjects and 3D OCT volume scans of the retina of porcine eyes. Results demonstrate that the proposed attenuation compensation procedure and retinal vessel extraction from OCT scans using Frangi filter is feasible. Matlab, Python, VolView and VTK software libraries were used for software analysis and visualization.
Dissertation or thesis originally submitted to the local University of Memphis Electronic Theses & dissertation (ETD) Repository.
Ahmed, Wasi Uddin, "Building 3-D Geometry of Retinal Vasculature From Optical Coherence Tomography Volume Scans" (2017). Electronic Theses and Dissertations. 1618.