Bulk motion subtraction in optical coherence tomography angiography
US10588572B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 7, 2017 |
| Grant date | Mar 17, 2020 |
| Priority date | — |
| Expiry date | Jul 23, 2038 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2207/30041
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.