Quantitative analysis of segmented fluorescein angiography images for the follow-up of choroidal neovascular membrane

Abstract

Purpose:The aim of this study was to evaluate choroidal neovascular (CNV) lesions with fluorescein angiography (FA) and to identify quantitative parameters and correlate these parameters to treatment outcomes.Subjects and Methods:This institution based cross-sectional study evaluated 30 eyes with active sub-foveal predominantly classic CNV treated with bevacizumab. Pre- and post-injection segmented FA images were analyzed. Lesion area and CNV lesion were manually delineated. Outcome measure was the change 1-month after each injection in different intensity values (0–255 divided in eight regions A [lowest intensity] to H [highest intensity] on a linear scale) in lesion area, perimeter, greatest linear dimension (GLD), area, visual acuity (VA) and central macular thickness (CMT).Results:At month 3, statistically significant changes from baseline occurred in VA, CMT, lesion area, GLD and perimeter (P < 0.05 all comparisons). Change in CMT from baseline to 3 months postinjection was correlated with change in VA (P = 0.009, r = 0.469) and intensity regions B (P = 0.001, r = −0.565), D (P = 0.001, r = 0.560), E (P = 0.035, r = 0.386). At month 3, change in intensity values 0–63 (A + B) was negatively correlated with CMT (P = 0.001, r = −0.575) and lesion area (P = 0.019, r = −0.427); change in intensity values 64–223 (C-G) was positively correlated with CMT (P = 0.000, r = 0.636) and lesion area (P = 0.002, r = 0.551).Conclusions:Decrease in area, GLD, perimeter and area with intensity ≥ 64 on segmented FA were associated with a favorable outcome of treatment. These parameters may be useful adjuncts to existing evaluation techniques during follow-up of CNV.