Phase-Stabilized Complex Decorrelation OCTA for Motion Artifact Removal
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Solution Overview
Problem
Current optical coherence tomography angiography (OCTA) methods face challenges in effectively removing bulk motion-induced artifacts and are often dependent on OCT reflectance, particularly in swept-source devices, which introduce noise due to trigger jitter, affecting the accuracy and dynamic range of flow detection.
Innovation Solution
The phase-stabilized complex decorrelation (PSCD) method stabilizes the phase signal by removing bulk motion and trigger jitter noise, using standard-deviation-based bulk motion compensation and spectrum-amplitude-based methods, to generate clean, high dynamic range angiograms across various OCT devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase-based OCTA processing is used to achieve high sensitivity to motion, then flow detection sensitivity is improved, but system phase and bulk motion noise vulnerability increases
Solution Approach 1:
The patent extracts and removes the bulk motion phase component from the complex OCT signal before performing decorrelation analysis. By separating the bulk motion phase (affecting all depths equally) from the flow-induced phase changes, the method preserves flow detection sensitivity while eliminating motion artifacts that would otherwise contaminate the measurement.
Solution Approach 2:
The patent introduces an intermediary processing step that calculates the bulk motion phase as a separate entity (using the standard deviation method across depths) and then compensates for it. This intermediary bulk motion phase estimate acts as a mediator that allows the system to maintain phase sensitivity while correcting for motion-induced phase errors.
2Measurement precision
If complex-based OCTA is used to utilize all reflectance signal information, then theoretical sensitivity is improved, but phase compensation requirement increases
Solution Approach 1:
The patent segments the phase information into two distinct components: bulk motion phase (affecting all depths uniformly) and flow-induced phase changes (local variations). By segmenting the phase compensation task, the method simplifies the overall complexity while maintaining the ability to utilize full complex signal information for flow detection.
Solution Approach 2:
The patent performs preliminary bulk motion phase compensation before the decorrelation analysis. By removing the bulk motion phase component in advance, the subsequent processing steps become simpler and less computationally intensive, while still benefiting from the full complex signal information.
3Device complexity
If amplitude-based OCTA is used to forego phase stabilization, then processing complexity is reduced, but flow detection sensitivity is lost
Solution Approach 1:
The patent replaces the need for complex hardware-based phase stabilization mechanisms with a computational approach. By using software-based bulk motion phase compensation algorithms, the system achieves phase stabilization without requiring additional hardware complexity, thereby maintaining sensitivity while keeping processing relatively simple.
Data Source
AI summary
Disclosed are methods and systems for phase-stabilized complex decorrelation (PSCD) optical coherence tomography (OCT) angiography (OCTA). In embodiments, a PSCD OCT A method includes performing phase stabilization on a complex-valued OCT data set to generate a phase-stabilized OCT dataset. The method further includes performing a complex decorrelation on the phase-stabilized OCT dataset to generate an OCTA dataset. One or more OCTA images may be generated based on the OCTA dataset. Other embodiments may be described and claimed.