Background: To compare ability of fluorescein angiography (FFA) and spectral-domain optical coherence tomography (SD-OCT) to diagnose subretinal neovascularization (SRNV) secondary to idiopathic juxtafoveal retinal telangiectasia (IJRT) type 2A.
Methods: Two masked observers evaluated FFA and SD-OCT images separately to diagnose the presence of SRNV in 65 eyes of 36 patients. A third masked observer diagnosed SRNV on color fundus photo. Presence of SRNV on color fundus photo was defined as presence of subretinal hemorrhage, thickening of retina, and/or visible membrane at the macula. Presence of SRNV on FFA was defined when there was hyperfluorescence in early phase with increase in intensity and size in the late phase; presence of membrane, large irregular lesion, hypofluorescence due to subretinal haemorrhage. SRNV on SD-OCT was defined as the presence of thickening of the retinal pigment epithelium-choriocapillaris complex with or without intraretinal fluid or subretinal fluid and associated with intraretinal hyperreflective area with retinal thickening.
Results: Interobserver agreement (Kappa) for diagnosis of SRNV on FFA and SD-OCT was 0.373 (95 % CI, 0.106-0.617) and 0.775 (95 % CI, 0.612-0.899) respectively. The sensitivity and specificity of FFA were 52.3 % and 70.0 % respectively. With regard to SD-OCT, the sensitivity and specificity were 72.7 % and 64.1 % respectively in reference to color photograph. The negative predictive value (NPV) of SD-OCT (80.6 %) was higher than FFA (73.7 %). When we considered only the presence of subretinal hemorrhage on color photograph as a confirmed diagnosis of SRNV and compared the diagnostic ability of FFA and SD-OCT, we found that the FFA had poor sensitivity (58.3 %) but a better specificity (71.8 %) than SD-OCT, which had sensitivity of 75 % and specificity of 64 % (Tables 1 and 2). However, the negative predictive value (NPV) of SD-OCT (89.29 %) was slightly better than FFA (84.85 %).
Conclusion: Interobserver agreement between the observers was better for SD-OCT than for FFA in making the diagnosis of SRNV. SD-OCT is a better diagnostic modality than FFA for ruling out the presence of SRNV.