Retinal Layer Segmentation in OCT Angiography

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Solution Overview

Problem

Conventional optical coherence tomography (OCT) methods are limited in detecting blood flow abnormalities such as capillary dropout or pathologic vessel growth, which are key features of age-related macular degeneration and proliferative diabetic retinopathy, due to their inability to directly detect blood flow or discriminate vascular tissue from surrounding tissue, and require invasive dye-based contrast agents.

Innovation Solution

The development of methods and systems for automated and manual segmentation of retinal layers in OCT scans, using directional graph search and manual editing techniques, to separate and visualize blood flow data into specific layers, facilitating analysis and visualization of ocular abnormalities like retinal and choroidal neovascularization, and macular edema.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual delineation of retina layer boundaries is performed by an experienced expert, then segmentation accuracy is improved, but time consumption and operator dependency increase

Engineering Contradiction:
Improvesegmentation accuracyVSAvoidtime consumption
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent segments the retinal image processing task into multiple components: automated boundary detection using image processing algorithms, extraction of layer boundary information, and optional manual refinement. This segmentation allows the system to perform initial accurate segmentation automatically, reducing time consumption while maintaining the option for expert review when needed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system implements self-service through automated segmentation algorithms that can independently process retinal images without requiring expert intervention for every case. The algorithm automatically detects layer boundaries, extracts features, and generates segmentation results, freeing experts from routine tasks while maintaining high accuracy through algorithmic consistency.

Inventive Principle:
Principle #25Self-service

2Productivity

If automated segmentation algorithms are used, then time efficiency is improved, but segmentation accuracy deteriorates in datasets with pathologies such as drusen, cystoid macular edema, subretinal fluid or pigment epithelial detachment

Engineering Contradiction:
Improvetime efficiencyVSAvoidsegmentation accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent implements a dynamic segmentation system that adapts its approach based on the characteristics of the input image. The algorithm automatically adjusts its parameters and processing steps according to the detected pathology type and severity, allowing it to maintain high accuracy across diverse pathological conditions while preserving time efficiency through automation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system incorporates feedback mechanisms where segmentation results are evaluated and used to refine subsequent processing steps. When pathologies are detected, the system adjusts its segmentation strategy based on feedback from intermediate processing stages, allowing it to correct for distortion effects and maintain accuracy in challenging cases.

Inventive Principle:
Principle #23Feedback

3Speed

If conventional structural OCT is used, then imaging speed is improved, but the ability to detect blood flow abnormalities deteriorates

Engineering Contradiction:
Improveimaging speedVSAvoidblood flow detection capability
Core Design Contradiction:
SpeedVSDifficulty of detecting and measuring

Solution Approach 1:

The patent merges structural OCT imaging with blood flow detection capabilities into a unified system. By combining the fast imaging speed of structural OCT with additional processing algorithms that extract blood flow information from the same dataset, the system achieves both rapid imaging and enhanced detection of vascular abnormalities without requiring separate imaging modalities.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system achieves multi-functionality by enabling a single OCT device to perform both structural imaging and blood flow detection. The same optical coherence tomography system can generate structural images for morphological assessment and simultaneously process the data to detect blood flow abnormalities, eliminating the need for separate imaging procedures and contrast agents.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables accurate and efficient segmentation of retinal layers, allowing for qualitative and quantitative assessment of blood flow and structural changes, reducing the need for invasive contrast agents and improving diagnostic accuracy in retinal pathologies.

Implementation Method 1

Optical coherence tomography (OCT) is a noninvasive, depth resolved, volumetric imaging technique that provides cross-sectional and three-dimensional (3D) imaging of biological tissues

Methodology Applied
Scientific EffectLight interference: Interference

Implementation Method 2

A limitation of conventional structural OCT, however, is that it is only sensitive to backscattered light intensity

Methodology Applied
Scientific EffectBackscattered light detection: Scattering

Implementation Method 3

OCT angiography is a refinement of the OCT imaging technique that uses the motion of red blood cells against static tissue as intrinsic contrast to allow visualization of blood flow

Methodology Applied
Scientific EffectMotion contrast:

Data Source

PatentUS10123689B2Systems and methods for retinal layer segmentation in OCT imaging and OCT angiography
Publication Date: 2018.11.13 OREGON HEALTH & SCI UNIV
  • US10123689B2 patent drawing
  • US10123689B2 patent drawing
  • US10123689B2 patent drawing

AI summary

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.