Dynamic versus Static Ultra-widefield Fluorescein Angiography in Eyes with Diabetic Retinopathy: A Pilot Prospective Cross-sectional Study

Background: Dynamic angiography can present additional information. However, evidence-based support in clinical application of dynamic modalities remain insufficient. The purpose of this study is to analyze differences in ultra-widefield fluorescein angiography (UWFA) findings between time-lapse dynamic and static imaging in eyes with diabetic retinopathy (DR).Methods: Twenty-eight eyes of 28 DR patients undergoing UWFA were included in the cross-sectional study. A series of UWFA images from each patient were converted into a time-lapse video in a Moving Picture Experts Group 4 movie format as a dynamic image. A single clear arteriovenous phase image was chosen as a static UWFA image. Non-perfusion index (NPI) and its correlation with intraretinal microvascular abnormality and neovascularization in different retinal zones were compared between dynamic and static UWFA imaging in severe nonproliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR).Results: NPI appeared to increase from the center to the far-periphery in both groups. Dynamic NPI appeared to be lower in the total retinal area (0.25 vs 0.28, p=0.005), far-periphery (0.30 vs 0.34, adjusted p=0.040) and superior quadrant (0.27 vs 0.34, adjusted p=0.045) in contrast to static NPI. Far-peripheral NPI was associated with intraretinal microvascular abnormality in posterior area in both groups.Conclusion: Time-lapse dynamic UWFA imaging is a useful method in the differential diagnosis of hypofluorescence in the most peripheral region, which may provide a reliable measurement of NPI and improve the diagnostic accuracy of DR.