Pre-processing of oct b-scans for oct angiography

A computer-implemented method of generating optical coherence tomography angiography, OCTA, data which provides a representation of vasculature of interest in an imaged region of a body part, the method comprising:

• receiving repeat B-scans of the imaged region of the body part acquired by an optical coherence tomography imaging apparatus;
• processing the repeat B-scans to generate respective cropped B-scans, the processing for each B-scan of the repeat B-scans comprising:
• selecting, from data elements of the B-Scan, a subset of the data elements such that the selected data elements are distributed along a representation of the body part in the B-scan;
• using the selected data elements to define a respective subregion of interest in the B-scan, the respective subregion of interest including OCT data acquired from the second subregion which contains the vasculature of interest;
• and
• generating the respective cropped B-scan by cropping the B-scan to leave the subregion of interest in the B-scan;
• and
• generating the OCTA data by processing the cropped B-scans.

An apparatus for processing repeat B-scans of an imaged region of a body part acquired by an optical coherence tomography, OCT, imaging apparatus, the imaged region including an anatomical feature confined to a first subregion of the imaged region and vasculature of interest confined to a second subregion of the imaged region, to generate cropped B-scans for use in generating OCT angiography data which provides a representation of the vasculature of interest, the apparatus comprising:

• a selection module arranged to process each B-scan of the repeat B-scans by selecting, from data elements of the B-scan, a respective subset of the data elements such that the selected data elements are distributed along a representation of the anatomical feature in the B-scan;
• a subregion defining module arranged to process each B-scan of the repeat B-scans by using the subset of data elements, which has been selected by the selection module from the data elements of the B-scan, to define a respective subregion of interest in the B-scan, the respective subregion of interest including OCT data acquired from the second subregion which contains the vasculature of interest;
• and
• a cropping module arranged to generate cropped B-scans by cropping each B-scan of the repeat B-scans to leave in the B-scan the respective subregion of interest defined for the B-scan by the subregion defining module.