Abstract
Purpose :
To evaluate the correlations between distinct retinal fluid volumes and optical coherence tomography angiography (OCTA)-derived macular neovascularization (MNV) parameters in patients with neovascular age-related macular degeneration (nAMD) at baseline (treatment-naïve) and during the anti-vascular endothelial growth factor therapy.
Methods :
A deep learning algorithm (RetInSight Fluid Monitor Version2) was used to automatically detect, localize, and quantify fluid in OCT (Spectralis,Heidelberg) volume scans. OCTA and high-density SD-OCT scans of patients obtained from multicenter studies from the Vienna Reading Center imaging database were evaluated. OCT & OCTA scans were performed continuously from baseline to week 64. OCTA-derived MNV parameters, such as lesion size (LS, the area covered by an MNV membrane) & vessel area (VA, the plain flow signal of a MNV membrane), were delineated and gathered by a reading center-certified retina specialist. A mixed model was used to evaluate associations between volumes of different fluid compartments and LS, VA & MNV type.
Results :
In total, OCT and OCTA volumes of 213 patients were evaluated. At baseline, the median amount within the central 6mm ETDRS ring was 156.6nl (IQR: 22.5;489.1) for subretinal fluid (SRF) and 3.1nl (IQR: 0.16;70.9) for intraretinal fluid (IRF) and 273.9nl (IQR: 32.7;699.7) for serous pigment epithelial detachment(sPED).
Using mixed linear models, we found a significant correlation between SRF volume and VA (estimate=256,p=0.002), a significant correlation between IRF volume and MNV type I (estimate: -27.5; p=0.003) and a significant correlation between sPED volume and VA (estimate:189.7;p=0.021). Considering SRF and sPED we also found a significant interaction between LS and VA, which was negative in the SRF model (estimate=-17.81;p=0.013) and positive in the sPED model (estimate=24.03;p=0.043).
Conclusions :
Larger neovascular areas in proportion to overall LS lead to higher amounts of SRF and sPED volume in eyes with nAMD, independently of the timepoint.
MNV maturation has an impact on disease activity in nAMD and can be used as a biomarker for exudation in the sub pigment epithelial or subretinal space. The amount of IRF solely depends on MNV type, with the highest volumes in type 3 followed by type 2 MNV.
Our data help to understand the biology of MNV and its clinically relevant retinal fluid activity.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.