[Observations of different presentations of choroid neovascularization in indocyanine green angiography]

The interpretation of choroidal neovascular membranes (CNV) in indocyanine green angiography (ICG-A) is difficult. It is not known whether demarcated hyperfluorescence in the ICG-A reliably reflects the true morphology and the total extent of a CNV. Therefore, in this retrospective study, the patterns of fluorescein and ICG angiograms were evaluated and compared in both occult and well-defined CNV. In 153 out of a total of 168 cases with CNV, age-related macular degeneration (AMD) was the underlying disease. CNV was occult in 114 and well-defined in 39 cases. The angiographic examinations with both dyes were performed with a modified fundus camera combined with a digital imaging system. In the group of AMD patients with occult or ill-defined CNV. 42 cases (36.8%) showed a defined membrane in the ICG stain. The filling patterns of ICG were extremely variable. In the group of AMD patients with classic CNV, ICG-A showed evidence of staining in the early and late phase in 14/39 cases (36%), exclusively in the early phase in 5/39 (13%) cases and only in the late phase in 17/39 cases (44%). Surprisingly, three well-defined membranes in fluorescein angiography (FLA) were not seen in any phase of the ICG-A. Compared with FLA, the 17 CNVs with demarcation only in the late phase of the ICG-A were seen to be larger in 8 and smaller in 9 cases while all CNVs seen in the early phase, or in both early and late phase, were of identical size with the early fluorescein staining. The pattern of ICG staining of CNV is complex. The single finding of a demarcated hyperfluorescence in the late phase of ICG-A should be interpreted with utmost caution, particularly in regard to planning laser therapy.