Oregon Health & Science University

Acner Camino

David E Huang

Yali Jia

Yan Li

Disclosed herein are methods and systems for automated detection of shadow artifacts in optical coherence tomography (OCT) and/or OCT angiography (OCTA). The shadow detection includes applying a machine-learning algorithm to the OCT dataset and the OCTA dataset to detect one or more shadow artifacts in the sample. The machine-learning algorithm is trained with first training data from first training samples that include manufactured shadows and no perfusion defects and second training data from second training samples that include perfusion defects and no manufactured shadows. The shadow artifacts in the OCTA dataset and/or OCT dataset may be suppressed to generate a shadow-suppressed OCTA dataset and/or a shadow-suppressed OCT dataset, respectively. Other embodiments may be described and claimed.

Automated detection of shadow artifacts in optical coherence tomography angiography

Described herein is an algorithm to remove decorrelation noise due to bulk motion in optical coherence tomography angiography (OCTA). OCTA B-frames are divided into segments within which the bulk motion velocity could be assumed constant. This velocity is recovered using linear regression of decorrelation versus the logarithm of reflectance in axial lines (A-lines) identified as bulk tissue by percentile analysis. The fitting parameters are used to calculate a reflectance-adjusted threshold for bulk motion decorrelation. Below this threshold, voxels are identified as non-flow tissue, and their flow values are set to zeros. Above this threshold, the voxels are identified as flow voxels and bulk motion velocity is subtracted from each using a nonlinear decorrelation-velocity relationship. Compared to the median-subtraction method, the bulk motion subtraction algorithm described herein improves angiogram signal-to-noise ratio, contrast, vessel density repeatability, and bulk motion noise cleanup, while preserving the connectivity of the vascular networks in the angiogram.

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Portland, OR, United States of America

Acner Camino