Application of Indocyanine Green Angiography for Cynomolgus Monkeys

Abstract

The recent widespread applications of fluorescein fundus angiography using indocyanine green as a contrast medium in the clinical field in humans are very much contributing to a number of active investigations conducted on various choroidal diseases such as age-related disciform macular degeneration, central serous chorioretinopathy and angioid streaks of retina. In this study, a novel case of indocyanine green angiographic application to cynomolgus monkeys is illustrated. Indocyanine green was first observed in choroidal vessels after 5.4±0.3 sec. of the intravenous administration of indocyanine green, and then in retinal arteries and veins. Immediately after the administration, a high level of insertion light caused overexposure, making the images of vessels obscure; therefore, the observations accompanied by the careful adjustment of the level of insertion light were needed. As fluorescence intensity in the vessels was getting to decline with the passage of time, the observations were conducted with an increasing level of insertion light aiming at obtaining the optimal images. The additional different angles of view for angiography were introduced, as demanded, to the analysis for the wide-ranging examinations on morphology and distribution patterns of individual vessels. After 9±1 min. of the administration, indocyanine green could no longer be observed in either retinal or choroidal vessel, but diffuse fluorescence throughout choroid.