Detection of choroidal neovascularization by subtraction indocyanine green angiography.

Background: Indocyanine green (ICG) angiography is considered to be an effective clinical tool to detect choroidal neovascularization (CNV) in age-related macular degeneration. However, CNV detection by angiography becomes difficult when a thick hemorrhagic lesion exists.

Methods: CNV was analyzed in 20 eyes (20 patients) showing age-related macular degeneration and accompanying subretinal hemorrhage using the subtraction method of ICG angiography.

Results: Subtraction ICG angiography revealed hyperfluorescent areas determined as dye leakage from CNV in all 20 cases. In 6 of the 20 cases, ill-defined fluorescence-increasing areas were observed which expanded during continuing angiography. On the other hand, the remaining 7 cases showed well-defined fluorescence-increasing areas which did not expand over time.

Conclusions: The subtraction method is an effective clinical tool to detect CNV concomitant with subretinal hemorrhage. Moreover, this method provides information to elucidate an increasing pattern of fluorescence surrounding CNV.