Rapid injection of indocyanine green dye for evaluation of choroidal venous circulation.

PURPOSE The purpose of this study was to investigate the effects of rapid intravenous administration of a small bolus of indocyanine green (ICG) dye on early phase findings of ICG angiography. METHODS Rabbit eyes were used. Ten normal eyes, 5 eyes with occlusion of vortex veins, and 5 eyes with chorioretinal atrophy were examined by ICG angiography, and early-phase findings after a rapid injection of a small bolus of dye were compared with those obtained with an ordinary injection. RESULTS In normal eyes, after the rapid injection it was possible to visualize some small bright fluorescent boluses in the choroidal veins from 6 to 12 seconds after injection, while with the ordinary injection they were unclear. In eyes with occlusion of vortex veins, the rapid injection resulted in visualization of the choroidal veins with delayed filling against the background, and the region of the choroidal veins with delayed filling could easily be determined. In eyes with chorioretinal atrophy, only the rapid injection clearly revealed the choroidal veins with delayed filling. CONCLUSIONS The rapid injection made it possible to detect the choroidal veins with delayed filling that were not clearly and easily visible using an ordinary injection. Rapid injection of ICG dye is useful for a detailed examination of choroidal circulation.