Optical coherence tomography angiography characteristics of choroidal neovascularizaiton in eyes with flat irregular pigment epithelial detachments

Abstract

Objective To assess the occurrence of CNV in patients presenting with flat irregular pigment epithelial detachments (FIPED). Methods Forty-five patients (49 eyes) with FIPED on OCT were enrolled in this retrospective study. There were 25 males (28 eyes) and 20 females (21 eyes). The mean age was 61.022±9.292 years. FFA, ICGA, spectral domain OCT and OCT angiography (OCTA) were performed in all patients during the same period. The FIPED was defined as an irregular elevation of the RPE allowing distinct visualization of Bruch’s membrane on OCT B-scan. The abnormal vascular signals from the deep retinal layer to the choroid layer on OCTA was defined as CNV. The CNV was classified into a type 1 CNV and a type 2 CNV according to the OCT characteristics. The CNV was classified into a typical and occult CNV according to the characteristics of the FFA image. Of all 49 eyes, fundus angiography revealed 18 eyes (36.7%) with CNV, and 31 eyes (63.3%) with no characteristic signs of CNV. FFA examination found that CNV in 8 eyes (classic CNV in 1 eyes, occult CNV in 7 eyes), which confirmed by OCT were type 1 CNV; transmitted fluorescence in 41 eyes. ICGA examination showed that CNV-like hyperfluorescence spots in 18 eyes, suspicious hyperfluorescence spots in late stage in 20 eyes, and choroidal high permeability in 11 eyes, respectively; and 18 CNV eyes were confirmed to be type 1 CNV by OCT. To compare the detection of CNV by OCTA and fundus angiography. Results Of the 49 eyes with FIPED, OCTA detected 36 eyes (73.5%) of type 1 CNV, and full or partial strong reflex signals were seen in FIPED; 13 eyes (26.5%) were not associated with CNV, and some strong reflection signals were found in FIPED in 9 eyes, 4 eyes with weak reflection signal. The FFA was examined for 1, 7 eyes of the classic and occult CNV, which confirmed to be type 1 CNV by OCTA. Among the 18 eyes with CNV which detected by ICGA, OCTA also found type 1 CNV. Among the 20 eyes with ICGA’s late suspicious strong fluorescent spots, OCTA showed 17 eyes of type 1 CNV; in 11 eyes with high choroidal permeability, OCTA showed type 1 CNV in 1 eye. Among the 36 eyes with CNV which detected by OCT, there were SRD in 32 eyes, no SRD in 2 eyes and retinal interlamellar cavities in 2 eyes. Conclusion OCTA can detect 73.5% of FIPED eyes with CNV. Compared with traditional fundus angiography, OCTA has a higher detection rate of CNV under FIPED. The FIPED of the internal strong reflection signal has a certain diagnostic value for the type 1 CNV. Key words: Flat irregular pigment epithelial detachments; Choroidal Neovascularization/diagnosis; Tomography, optical coherence; Fluorescein angiography; Indocyanine green/diagnostic use