Analysis of Choroidal Arterial, Choriocapillary, and Venous Circulation using High-speed Subtraction ICG Angiography

Abstract

Abstract: : Purpose: To demonstrate the usefulness of high-speed subtraction ICG angiography (ICGA) to access the change of choroidal circulation patterns during cardiac cycle. Methods: Five healthy young volunteers and 5 patients with uveitis were examined. ICG solution (2ml; 25 mg dissolved in 2 ml of manufacturer-supplied distilled water) was injected into a dorsal vein, immediately followed by a 5 ml saline flush. ICG angiograms were obtained 15 images/second during the dye transit phase with a newly-developed TOPCON infla-red fundus camera. The subtraction analysis were performed on original ICG images which were taken in 0.2 second interval, by TOPCON IMAGEnet system . Results: In healthy young volunteers, choroidal arteries were imaged in the first 2 cardiac cycles, then choriocapillaris (CC) and choroidal veins were imaged in the following cycles. In uveitis patients, quick or slow flow from choroidal artries to veins was visualized in each cardiac cycle. Delayed filling in the choroidal circulation was detected separately in the choroidal arteries, CC, or choroidal veins. Conclusions: Analysis of blood flow in the choroidal arteries, CC, or veins is now possible using high-speed subtraction ICGA. This method is useful for a detailed examination of choroidal circulation.

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, S • choroid • imaging/image analysis: clinical