A computer-implemented method of processing optical coherence tomography angiography, OCTA, data comprising an array of columns (212-1 to 212-W) of data elements, which represents a distribution of vasculature in an imaged region of a body part, to generate corrected OCTA data showing reduced projection artefacts in enface projection relative to the OCTA data, the data elements in each column of the array of columns (212-1 to 212-W) having been generated from data elements of OCT data that are correspondingly located in A-scans of respective B-scans of a set of repeat B-scans (251, 253, 255, 257) of the imaged region of the body part, the method comprising processing data elements of the OCT data and data elements of the OCTA data by processes of: (i) calculating a correlation value that is indicative of a degree of correlation between a first sequence of data elements (d OCT1 (i, j), d OCT2 (i, j), d OCT3 (i, j), d OCT4 (i, j)), of the OCT data, wherein respective locations of the data elements of the first sequence within the respective B-scans (B-scan 1 to B-scan 4) correspond to a location of a first data element (d OCTA (i, j)) within the array of columns of the OCTA data, and a second sequence of data elements (d OCT1 (i, k), d OCT2 (i, k), d OCT3 (i, k), d OCT4 (i, k)) of the OCT data, wherein respective locations of the data elements of the second sequence within the respective B-scans (B-scan 1 to B-scan 4) correspond to a location of a second data element within the array of columns of the OCTA data, the second data element being further along in an axial direction (z) of the OCTA data, in which the columns (212-1 to 212-W) of the OCTA data extend, than the first data element; (ii) using the first data element and the calculated correlation value to calculate a correction for the second data element; and (iii) applying the calculated correction to the second data element, wherein processes (i) to (iii) are performed multiple times, using a different combination of a data element of the OCTA data as the first data element and a data element of the OCTA data as the second data element in each performance of processes (i) to (iii), so as to generate the corrected OCTA data. (i) calculating a correlation value that is indicative of a degree of correlation between a first sequence of data elements (d OCT1 (i, j), d OCT2 (i, j), d OCT3 (i, j), d OCT4 (i, j)), of the OCT data, wherein respective locations of the data elements of the first sequence within the respective B-scans (B-scan 1 to B-scan 4) correspond to a location of a first data element (d OCTA (i, j)) within the array of columns of the OCTA data, and a second sequence of data elements (d OCT1 (i, k), d OCT2 (i, k), d OCT3 (i, k), d OCT4 (i, k)) of the OCT data, wherein respective locations of the data elements of the second sequence within the respective B-scans (B-scan 1 to B-scan 4) correspond to a location of a second data element within the array of columns of the OCTA data, the second data element being further along in an axial direction (z) of the OCTA data, in which the columns (212-1 to 212-W) of the OCTA data extend, than the first data element; a first sequence of data elements (d OCT1 (i, j), d OCT2 (i, j), d OCT3 (i, j), d OCT4 (i, j)), of the OCT data, wherein respective locations of the data elements of the first sequence within the respective B-scans (B-scan 1 to B-scan 4) correspond to a location of a first data element (d OCTA (i, j)) within the array of columns of the OCTA data, and a second sequence of data elements (d OCT1 (i, k), d OCT2 (i, k), d OCT3 (i, k), d OCT4 (i, k)) of the OCT data, wherein respective locations of the data elements of the second sequence within the respective B-scans (B-scan 1 to B-scan 4) correspond to a location of a second data element within the array of columns of the OCTA data, the second data element being further along in an axial direction (z) of the OCTA data, in which the columns (212-1 to 212-W) of the OCTA data extend, than the first data element; (ii) using the first data element and the calculated correlation value to calculate a correction for the second data element; and (iii) applying the calculated correction to the second data element,