Systems and methods for retinal layer segmentation in OCT imaging and OCT angiography
Disclosed herein are methods and systems for segmenting, visualizing, and quantifying the layered structure of retina in optical coherence tomography datasets. The disclosed methods have particular application to OCT angiography data, where specific retina layers have distinct vascular structures and characteristics that can be altered in various pathological conditions of the eye.
1. A method of editing a retina layer boundary segmentation comprising:
receiving a set of structural OCT B-scans;
segmenting the retinal layer boundaries of the structural OCT B-scans by the steps of:
a) receiving a set of relative retinal layer thickness data;
b) enhancing intensity transition in the structural OCT B-scan images;
c) selectin a first B-scan image from the set of structural OCT B-scans;
d) selecting a first retinal layer boundary in the first B-scan image;
e) applying a directional graph search to the first retinal layer boundary, thereby generating a first segmented retinal layer boundary;
f) selecting a second retinal layer boundary on the first B-scan image;
g) constraining a search region of the second retinal layer boundary using the first segmented retinal layer boundary and the set of relative retinal layer thickness data; and
h) applying a directional graph search to the second retinal layer boundary; thereby generating a second segmented retinal layer boundary; thereby generating a set of segmented retinal layer boundaries;
reviewing the set of segmented retinal layer boundaries;
selecting a segmented retinal layer boundary in a B-scan;
editing the segmented retinal layer boundary in a B-scan using an intelligent scissors tool based on directed graph search, or a portion thereof, thereby creating a new retinal layer boundary segmentation; and
propagating the new retinal layer boundary segmentation to adjacent structural OCT B-scans.
2. A method of analyzing OCT angiography data comprising:
receiving a set of structural OCT B-scans;
receiving a set of OCT angiography B-scans;
segmenting the retina layers in the structural OCT B-scans, by the steps of:
a) receiving a set of relative retinal layer thickness data;
b) enhancing intensity transition in the structural OCT B-scan images;
c) selecting a first B-scan image from the set of structural OCT B-scans;
d) selecting a first retinal layer boundary in the first B-scan image;
e) applying a directional graph search to the first retinal layer boundary, thereby generating a first segmented retinal layer boundary;
f) selecting a second retinal layer boundary on the first B-scan image;
g) constraining a search region of the second retinal layer boundary using the first segmented retinal layer boundary and the set of relative retinal layer thickness data; and
applying a directional graph search to the second retinal layer boundary; thereby generating a second segmented retinal layer boundary: thereby generating a set of segmented retina layer boundaries;
defining a retinal layer slab, wherein the upper and lower extents of the retinal layer slab are defined using the segmented retina layer boundaries;
color-coding flow data from the set of OCT angiography B-scans based on the retinal layer slab in which it resides;
merging the color-coded flow data from the set of OCT angiography B-scans with structural OCT data from the set of structural OCT B-scans, thereby generating composite OCT data;
presenting composite OCT data.
3. The method of claim 2 wherein presenting the composite OCT data comprises generation of a color-coded 2D en face angiogram.