Mapping the 3D Connectivity of the Rat Inner Retinal Vascular Network Using OCT Angiography.
OBJECTIVE
The purpose of this study is to demonstrate three-dimensional (3D) graphing based on optical coherence tomography (OCT) angiography for characterization of the inner retinal vascular architecture and determination of its topologic principles.


METHODS
Rat eyes (N = 3) were imaged with a 1300-nm spectral/Fourier domain OCT microscope. A topologic model of the inner retinal vascular network was obtained from OCT angiography data using a combination of automated and manually-guided image processing techniques. Using a resistive network model, with experimentally-quantified flow in major retinal vessels near the optic nerve head as boundary conditions, theoretical changes in the distribution of flow induced by vessel dilations were inferred.


RESULTS
A topologically-representative 3D vectorized graph of the inner retinal vasculature, derived from OCT angiography data, is presented. The laminar and compartmental connectivity of the vasculature are characterized. In contrast to sparse connectivity between the superficial vitreal vasculature and capillary plexuses of the inner retina, connectivity between the two capillary plexus layers is dense. Simulated dilation of single arterioles is shown to produce both localized and lamina-specific changes in blood flow, while dilation of capillaries in a given retinal vascular layer is shown to lead to increased total flow in that layer.


CONCLUSIONS
Our graphing and modeling data suggest that vascular architecture enables both local and lamina-specific control of blood flow in the inner retina. The imaging, graph analysis, and modeling approach presented here will help provide a detailed characterization of vascular changes in a variety of retinal diseases, both in experimental preclinical models and human subjects.
Department of Biomedical Engineering, University of California Davis, Davis, California, United States.
Conor
C
Leahy
Department of Biomedical Engineering, University of California Davis, Davis, California, United States.
Harsha
H
Radhakrishnan
Shiley Eye Institute, University of California San Diego, San Diego, California, United States.
Geoffrey
G
Weiner
Shiley Eye Institute, University of California San Diego, San Diego, California, United States.
Jeffrey L
JL
Goldberg
Department of Biomedical Engineering, University of California Davis, Davis, California, United States 3Department of Ophthalmology and Vision Science, University of California Davis School of Medicine, Sacramento, California, United States.
Vivek J
VJ
Srinivasan
D000818:Animals; D002196:Capillaries / Q000033:anatomy & histology; D005451:Fluorescein Angiography; D021621:Imaging, Three-Dimensional / Q000379:methods; D009898:Optic Disk / Q000098:blood supply*; D051381:Rats; D012039:Regional Blood Flow; D012171:Retinal Vessels / Q000033:anatomy & histology* / Q000502:physiology; D041623:Tomography, Optical Coherence / Q000379:methods*