Retinal pigment epithelium hyperplasia overlying pigment epithelial detachment in age-related macular degeneration can masquerade as neovascularization on optical coherence tomography angiography

Abstract

Purpose: To report the image artifacts due to retinal pigment epithelium (RPE) hyperplasia overlying retinal pigment epithelial detachment (PED) in age-related macular degeneration (AMD), which can masquerade as neovascularization on optical coherence tomography angiography (OCTA).

Methods: A hospital-based, retrospective, and cross-sectional study. Twenty-two eyes from 16 patients with non-vascularized PED related to AMD were included in this study. All patients were examined by OCTA, spectral-domain optical coherence tomography, fluorescence angiography, and indocyanine green angiography. Vascular flow signals (VFS) on both the outer retinal slab of en face OCTA and cross-sectional OCTA and their correspondence with RPE hyperplasia were evaluated.

Results: Fifteen eyes (68.2%) showed VFS on both the outer retina slab of en face OCTA and cross-sectional OCTA, all corresponding to the RPE hyperplasia overlying PED. Among them, 12 eyes with lump RPE hyperplasia outside foveal avascular zone (FAZ) all showed obvious VFS on the outer retina slab of OCTA, and 3 eyes with scattered RPE hyperplasia outside FAZ showed VFS fragments. Of note, 4 eyes had accompanied RPE hyperplasia inside FAZ, and 7 eyes without RPE hyperplasia overlying PED showed no corresponding VFS on the outer retina slab of OCTA. Additionally, a round-like dark band at the edge of PED was observed in the outer retina slab on en face OCTA in 17 eyes (77.3%).

Conclusions: RPE hyperplasia overlying PED in AMD can masquerade as neovascularization on OCTA. To avoid misdiagnosis and unnecessary treatment, this RPE hyperplasia-related image artifact should be considered when interpreting OCTA images.

Keywords: Age-related macular degeneration; Image artifacts; Optical coherence tomography angiography; Pigment epithelial detachment; Retinal pigment epithelium hyperplasia.

Fig. 1

Multimodal imaging of non-vascularized PED in AMD with lump RPE hyperplasia outside the central foveal avascular zone. A non-vascularized PED imaged on color fundus photography (a), fundus autofluorescence (b), late-phase fundus fluorescein angiography (c), late-phase indocyanine green angiography (d), infrared fundus photography (e), spectral-domain optical coherence tomography (f), the outer retina slab on en face OCTA (g), cross-sectional OCTA, and cross-sectional OCT with segmentation boundary lines (h and i). The solid line in e shows the location of B-scans in f. The asterisk shows the sub-retinal fluid. The dotted line in g shows the location of B-scans in h and i. The long yellow arrow shows the abnormal flow corresponding to the RPE hyperplasia overlying PED at the same location. The short white arrows show the round-like dark band around the edge of PED

Fig. 2

Multimodal imaging of non-vascularized PED in AMD with scattered RPE hyperplasia outside the central foveal avascular zone. A non-vascularized PED imaged on color fundus photography (a), late-phase fundus fluorescein angiography (b), late-phase indocyanine green angiography (c), the outer retina slab on en face OCTA (d), and cross-sectional OCTA with segmentation boundary lines (e). The dotted line shows the location of B-scans in e. The long red arrow shows the abnormal flow corresponding to the RPE hyperplasia overlying PED. The short white arrow in d shows the round-like dark band around the edge of PED. The short white arrow in e shows the steep edge of PED where the RPE was not segmented into the outer retina slab

Fig. 3

Multimodal imaging of non-vascularized PED in AMD with RPE hyperplasia inside and outside the central foveal avascular zone. A non-vascularized PED imaged on color fundus photography (a), infrared fundus photography (b), late-phase fundus fluorescein angiography (c), late-phase indocyanine green angiography (d), the superficial retinal slab on en face OCTA (e), the outer retina slab on en face OCTA (f), the cross-sectional OCTA through the foveal with segmentation boundary lines (g), and the cross-sectional OCTA outside the foveal with segmentation boundary lines (h). The dotted red circle in a–f shows the central foveal avascular zone (FAZ). The dotted red line in f shows the location of B-scan in g, which was through the foveal. The dotted yellow line in f shows the location of B-scan in h. The red arrow in g shows the RPE hyperplasia inside the central FAZ, with no abnormal vascular flow signal was shown. The yellow arrow in f and h shows the abnormal vascular flow corresponding to the RPE hyperplasia outside the central FAZ

Fig. 4

Non-vascularized PED in AMD without RPE hyperplasia and abnormal vascular flow signals on OCTA. A non-vascularized PED imaged on the color fundus photography (a), the late-phase fundus fluorescein angiography (b), the en face OCT (c), the cross-sectional OCT with segmentation boundary lines (d), the outer retina slab on en face OCTA (e), and the cross-sectional OCTA with segmentation boundary lines (f). The dotted line in c shows the location of B-scans in d. The dotted line in e shows the location of B-scans in f. The short white arrows in a, b, c, and e show the edge of PED. There is no RPE hyperplasia overlying PED inside and outside the central FAZ. And no vascular flow signal was observed at the outer retina slab of en face OCTA and the cross-sectional OCTA