Diabetic Microaneurysms Internal Reflectivity on Spectral-Domain Optical Coherence Tomography and Optical Coherence Tomography Angiography Detection

Abstract

To correlate the appearance of microaneurysms (MAs) on structural spectral-domain optical coherence tomography (SDOCT) with their detection on OCT angiography (OCTA) in patients with nonproliferative diabetic retinopathy (NPDR). Interinstrument reliability study. Sixteen patients with NPDR without macular edema underwent SDOCT and OCTA. To compare MAs seen on OCTA with those on SDOCT, we superimposed the OCTA superficial capillary plexus (SCP) vascular landmarks onto those of the near infrared. Two observers masked to patient groupings evaluated reflectivity of MAs on SDOCT scans, graded as hyporeflective, moderate, or hyperreflective, and their visualization at the level of SCP and deep capillary plexus (DCP) on OCTA. Among 145 MAs imaged with SDOCT, 47 (32.4%) appeared as hyperreflective, 71 (49.0%) as moderately reflective, and 27 (18.6%) as hyporeflective. After excluding 3 eyes (10 MAs) because of poor-quality OCTA scans, 135 MAs were evaluated on OCTA; 76 (56.3%) were visible only in the DCP, 9 (6.7%) only in the SCP, 29 (21.5%) were visible in both SCP and DCP; and 21 (15.6%) were not visible on OCTA. Compared with MAs with hyperreflectivity or moderate reflectivity, MAs with hyporeflectivity on structural SDOCT were significantly less likely to be detected on OCTA (odds ratio [OR]: 4.6; 95% confidence interval [CI]: 1.5-14.0, P= .008; and OR: 4.2, 95% CI: 1.2-14.2, P= .022, respectively). MAs that appear hyporeflective on structural SDOCT have a lower detection rate on OCTA. The results of this study may help further understand the different blood flow dynamics pattern in MAs.