A Comparison of Optical Coherence Tomography (OCT) and Fluorescein Angiography (FA) in The Diagnosis and Assessment of Diabetic Macular Edema

Abstract

Purpose: : To study the accuracy of OCT in the diagnosis and assessment of diabetic macular edema (DME) as compared to the widely used FA for the evaluation of this disease process.

Methods: : We performed a retrospective analysis of 198 OCT and FA images (1 image per eye) for 99 patients with presumed DME. These images were selected from our database using the diabetic retinopathy code and were assigned a number between 1 and 99. Each set of images consisted of an FA and an OCT. The images were independently interpreted by two retina specialists and two retina fellows. The responses were then categorized into two groups: "macular edema" or "no macular edema" and this data was analyzed using a Chi-squared Test for each eye.

Results: : A statistically significant difference (Pr ≥ 0.010) was calculated in 7:8 sets for images scored with "macular edema" by FA versus OCT. Percent OCT positive diagnosis of macular edema per interpreter ranged from 0.298 + 0.459 to 0.652 + 0.478 while diagnosis by FA ranged from 0.399 + 0.491 to 0.520 + 0.501. However, individual physicians varied in whether or not they detected more cases of macular edema by FA or OCT, and neither method showed a clear diagnostic advantage.

Conclusions: : Diagnosis of diabetic macular edema by OCT yields statistically significant differences when compared to diagnosis by FA. While both modalities may complement each other in the ultimate diagnosis of DME for individual cases, different physicians might make significantly more positive diagnoses by using one modality versus the other. Diagnosis of DME may still require astute clinical judgment rather than reliance on one modality over another.

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • imaging/image analysis: clinical • edema