Purpose: To study the correspondence between fluorescein angiography (FA) and structural en face optical coherence tomography (OCT) in the identification of leaky microaneurysms in diabetic macular edema (DME).
Methods: Fourteen eyes of eight patients with DME (6 males and 2 females, mean age 67.3 ± 8.5) were included. For all eyes, a 6 × 6 mm structural en face image of the middle retina was obtained and superimposed on a FA image. The reflectivity, capsulation, and association with intraretinal cystic fluid (IRCF) of microaneurysms on en face were evaluated depending on their leaky status on FA.
Results: Out of the 320 leaky microaneurysms evaluated, 280 (89.0 ± 8.2%) coincided with those on en face OCT image. Twenty-nine (10.6 ± 6.9%) and 20 (6.5 ± 7.8%) out of all leaky microaneurysms were hyperreflective and demonstrated capsular appearance, respectively. A majority of leaky microaneurysms (97.9 ± 3.2%) were associated with IRCF. From 146 microaneurysms which were found only on en face images, 130 (88.2% ± 15.7%) were hyperreflective, 33 (23.9% ± 15.6%) demonstrated capsular structure, and 13 (9.2% ± 15.0%) demonstrated no associated IRCF. After exclusion of microaneurysms of the inner retina, 95.4 ± 5.4% of leaky microaneurysms were identified on en face image. En face imaging demonstrated 83.5% sensitivity and 89.4% specificity (the area under the curve 0.87) in the identification of leaky microaneurysms.
Conclusions: Structural en face imaging is comparable to FA in identification of leaky microaneurysms in diabetic macular edema. Moderate reflectivity, the absence of capsular structure, and neighboring intraretinal cystic fluid indicate leaky microaneurysms.
Keywords: Diabetic macular edema; Fluorescein angiography; Focal laser photocoagulation; Microaneurysms; Optical coherence tomography; Optical coherence tomography angiography.