Microaneurysm Imaging Using Multiple En Face OCT Angiography Image Averaging: Morphology and Visualization

Abstract

In diabetic retinopathy (DR), OCT angiography (OCTA) could not image all fluorescein angiography (FA)-detected microaneurysms. We investigated whether multiple image averaging could enhance the microaneurysm detection capability of OCTA in patients with DR. Prospective and cross-sectional observational study. Consecutive 31 patients (n= 62 eyes) with DR. All eyes underwent FA and 3× 3 mm fovea-centered OCTA images were obtained using 2 devices: RTVue XR Avanti (Optovue Inc, Fremont, CA) and OCT HS-100 (Canon Inc, Toyko, Japan). OCTA imaging (HS-100) was performed 10 consecutive times. Microaneurysm detection capability was compared among 5 OCTA images (single image,×3,×5, and×10 averaged images and single scan image with the RTVue XR Avanti device). Microaneurysm detection capability and the correlation between microaneurysm clinical characteristics or morphology and the extent of image averaging required for OCTA detection. A total of 415 microaneurysms could be analyzed in 31 eyes from 25 patients. Microaneurysms detected on single image,×3,×5, and×10 averaged OCTA images were 144 (34.7%), 227 (54.7%), 285 (68.7%), and 306 (73.7%), respectively. Microaneurysm detection capability was significantly increased with increased image averaging. Microaneurysm detection with OCTA was not correlated with retinal thickness, FA leakiness, and indocyanine green angiogram detection or the number of averaged images, whereas there was significant correlation between microaneurysm morphology and microaneurysm visibility by the image-averaging process for 4 morphologies, particular the focal bulge types (P < 0.01). In DR, multiple image averaging is useful for increasing the microaneurysm detection capability of OCTA, especially for focal bulge-type microaneurysms.