Stepwise segmentation error correction in optical coherence tomography angiography images of patients with diabetic macular edema
Reza Mirshahi1 , Khalil Ghasemi Falavarjani 1 *
- Eye Research Center, The Five Senses Institute, Rassoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran
Abstract: To determine the minimum number of OCT B-scan corrections required to provide acceptable vessel density measurements on optical coherence tomography angiography (OCTA) metrics in eyes with diabetic macular edema (DME)
Methods: In this prospective, non-interventional case series, the OCTA images of eyes with center-involving DME were included. Segmentation error was recorded and manually corrected in the inner retinal layers in the central foveal, 100th and 200th OCT B-scans. The segmentation error correction was then continued until all OCT B-scans in whole en face image were corrected. At each step, the manual correction of each OCT B-scan was propagated to whole image. The vessel density (VD) and retinal thickness were recorded at baseline and after each OCT B-scan correction.
Results: Thirty-six eyes of 26 patients. To achieve full segmentation error correction in whole en face image, an average of 1.72±1.81 and 5.57±3.87 B scans were corrected in inner plexiform layer (IPL) and outer plexiform layer (OPL), respectively. The change in the VD measurements after complete segmentation error was statistically significant after IPL correction. However, no statistically significant change in VD was found after manual correction of the OPL. The VD measurements at DCP was statistically significantly different after single central foveal B-scan correction of IPL compared to the baseline measurements (P=0.03), however, it remained unchanged after further segmentation corrections of IPL.
Conclusion: Although several OCT B-scans should be manually corrected for an en face OCTA image, the central foveal B-scan correction provides the most significant change in VD measurements.
