Comparative analysis of OCT-angiography and fluorescein angiography in imaging diabetic retinopathy: Unveiling new diagnostic insights

Abstract

Purpose

To compare and evaluate the diagnostic performance of OCT-angiography (OCT-A) parameters in diabetic retinopathy (DR) detection compared to fluorescein angiography (FA).

Methods

This is a cross-sectional, prospective study including 118 diabetic patients (214 eyes). All patients had a complete clinical examination with FA as well as macular OCT-A imaging (3 × 3 mm, 6 × 6 mm). We compared the detection of fundamental DR lesions using both imaging modalities and assessed the diagnostic value of different OCT-A parameters.

Results

Microaneurysms were more frequently detected by FA than with OCT-A. Intraretinal microvascular anomalies were equally visualized by OCT-A (0.27 ± 0.777) and FA (0.27 ± 0.71). Average of foveal avascular zone (FAZ) surface was less significant at superficial capillary plexus (SCP) (0.353 ± 0.107 mm²) compared to deep capillary plexus (DCP) (0.537 ± 0,135 mm²), (p < 0.001). FAZ remodeling was observed even in DR free eyes and was better identified in DCP (61.1%) than SCP (47.2%). Loss of FAZ circularity was estimated at 0.792 ± 0.081 and 0.741 ± 0.107 respectively in SCP and DCP, (p < 0.001). Average surface area of capillary non-perfusion zones (CNPZ) was 0.487 ± 0.514 mm² in SCP and 0.145 ± 0.223 mm² in DCP, (p < 0.001). The Most reliable OCT-A quantitative parameters for DR screening were: CNPZ surface in DCP (p = 0.0046), total vascular density (VDt) in the DCP (p = 0.003) and CNPZ surface in the SCP (p = 0.0027).

Conclusion

OCT-A enables diabetic microvascular abnormalities detection even at a preclinical stage. Certain OCT-A parameters may provide a valuable quantitative approach for diagnosis and grading of DR severity.