Characterization of diabetic microaneurysms by simultaneous fluorescein angiography and spectral-domain optical coherence tomography

Purpose: To correlate spectral-domain optical coherence tomography (SD-OCT) findings of perfused diabetic microaneurysms with leakage status on fluorescein angiography (FA) using simultaneous FA and SD-OCT.

Design: Retrospective, observational case series.

Methods: A total of 173 microaneurysms were analyzed in 50 eyes (14 mild nonproliferative diabetic retinopathy [NPDR]; 22 moderate NPDR; 9 severe NPDR; 5 proliferative diabetic retinopathy) of 40 diabetic patients using simultaneous FA and SD-OCT. The characteristics of microaneurysms were evaluated by 2 masked observers using SD-OCT and correlated with leakage status on FA.

Results: External diameter of microaneurysms averaged 104 μm (range 43-266 μm). Some microaneurysm centers (15/173; 9%) and the outermost extent of microaneurysms (113/173; 68%) were localized to the outer half of the retina. Almost all microaneurysms spanned more than 1 retinal layer (157/173; 91%). Most microaneurysms had an internal lumen with homogeneous reflectivity (109/173; 63%) and moderate reflectivity (87/173; 50%). Retinal thickness through microaneurysms as well as the presence of adjacent hyporeflectivity on SD-OCT correlated with increasing leakage status seen on FA (P < .001). Microaneurysm dimensions, percent depth within the retina, retinal layer location, and internal reflectivity by SD-OCT did not correlate significantly with FA leakage status.

Conclusions: Simultaneous FA and SD-OCT allows detailed characterization of perfused diabetic microaneurysms. Increased FA leakage of diabetic microaneurysms positively correlated with perianeurysm fluid and retinal thickness. Perfused microaneurysms seen by SD-OCT were localized deeper than the inner nuclear layer.