A Comparison of Neovascular Age-Related Macular Degeneration Features in OCT Angiography and Fluorescein Angiography

Abstract

Purpose : Many pathological features in neovascular age-related macular degeneration (nAMD) can be assessed on both OCT Angiography (OCTA) and fluorescein angiography (FA). We compared macular neovascularization (MNV) and lesion area between OCTA and FA.

Methods : OCTA and FA images from 30 subjects with treatment naïve nAMD across multiple clinical trials were included at baseline. MNV area (mm²), lesion area within ETDRS grid (mm²), MNV type, and MNV presence at center point were evaluated from OCTA (VisionIX or Carl Zeiss Meditec) and FA. Total leakage area within the ETDRS grid (mm²) was assessed on FA. For OCTA, MNV area was defined on the angiogram using the flow signal within RPE elevation on the cross-sectional scan. OCTA lesion area was defined as the area involving RPE elevation with adjacent regions of blocked signal and atrophy. MNV from FA was identified by area of hyperfluorescence seen in early/mid phase associated with leakage in late phase. FA lesion area was defined by the MNV and associated lesion components. Comparisons of features assessed on OCTA versus FA were performed.

Results : MNV was measurable for 28 of 30 subjects on OCTA and for all subjects on FA. All subjects had assessable lesion area on OCTA and FA. Mean MNV area and lesion area on OCTA were 1.91±2.17 mm² and 5.45±5.77 mm². For FA, the measurements were 4.86±5.44 mm² and 5.43±5.91 mm² respectively. Mean difference between the two modalities was 2.95±3.70 mm² (r=0.91) for MNV area and 0.03±0.053 mm² (r=0.99) for lesion area. Leakage area on FA was correlated with MNV and lesion areas on OCTA (r=0.886 and r=0.942 respectively). Lesions were measured at similar locations on both imaging types (Figure 1, A-B) but the general shape of the lesions varied (Figure 1, C-D). Between OCTA and FA, there was modest agreement on MNV center point involvement (71.4%, p<0.05); type of MNV lesions had poor agreement (44%, p=0.40).

Conclusions : While OCTA and FA appear to identify similar presence of both MNV and the associated lesion, there was a significant difference in the MNV area measurements between the two modalities. Longitudinal studies on treatment response are needed to further understand the role of FA and OCTA in clinical trials.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.

 

Figure 1. Panels A (OCTA) and B (FA) have similar lesion areas and borders (3.71 mm² vs 3.68 mm²) while panels C (OCTA) and D (FA) have differing borders (5.10 mm² vs 5.28 mm²).