NEW METHOD FOR REDUCING ARTIFACTUAL FLOW DEFICITS CAUSED BY COMPENSATION TECHNIQUES IN THE CHORIOCAPILLARIS WITH OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY.

Abstract

To mitigate artifactual choriocapillaris flow deficits in optical coherence tomography angiography, which are a side effect of inverse structural optical coherence tomography compensation. In a modified algorithm, we set pixels in the original structural optical coherence tomography that were greater than one SD above the mean intensity (hyperreflective regions) to the mean pixel intensity of the image to remove hyporeflective regions in the inverse slab. We compared this algorithm to the original using flow deficit density and multiscale structural similarity index obtained from three distinct thresholding methods (local Phansalkar, global MinError (I), and global Li). We included 16 eyes of 16 healthy subjects (31.1 ± 6.9 years, 10 females). Using the modified optical coherence tomography correction, flow deficit density was lower compared with the original algorithm using Phansalkar (P < 0.001) but higher using Li thresholding (P = 0.049). Multiscale structural similarity index was increased after applying the modified algorithm with all three thresholding methods (P < 0.001), indicating a closer relationship to the original optical coherence tomography angiography scan. We demonstrate a new method that significantly reduced the introduction of artifactual flow deficits in the choriocapillaris during postprocessing. Given the improved multiscale structural similarity index, we believe our algorithm more accurately represents the choriocapillaris.