"Neovascular Network Ingrowth Site Characterization in Polypoidal Choroidal Vasculopathy by Conventional Digital Indocyanine Green Angiography."

Abstract

Abstract: : Purpose: To evaluate the feasibility of neovascular network ingrowth site identification in patients with polypoidal choroidal vasculopathy (PCV) by using a conventional high–resolution digital angiography device. Methods: Observational case series. Patients evaluated at a tertiary referral center with a diagnosis of PCV were invited to participate in a comprehensive ophthalmic evaluation, including best–corrected ETDRS visual acuity measurement, color fundus photography, and conventional angiographic studies (fluorescein and indocyanine green [ICG]). For the latter, a two–fold scheme of ICG dye infusion was utilized. The neovascular vessels (NVs) and PCV network ingrowth site were identified by comparing early– and late–phase ICG angiographic digital images to each other and to fluorescein angiograms. Results: Nineteen eyes of thirteen consecutive patients were studied. Early phase ICG angiography enabled clear identification of the PCV NVs in 18 out of 19 studied cases. Observation of the ICG dye–filling pattern within the PCV network revealed two distinct varieties of NVs. Typically, some NVs characterized by early filling (concomitant to the retinal arteries filling) and rapid transit (1.1 to 2.7 seconds) (Type A) were seen followed (1.0 to 1.9 seconds later) by the filling of several NVs in which an extended dye transit period was observed (7.8 seconds to several minutes) (Type B). The location of the PCV ingrowth site, based on the disposition of NVs Type A, was peripapillary in 12 eyes (mostly at the supero–temporal region), within de macular region in 5 eyes, and extra–macular in one. Focal treatment of the PCV ingrowth site by ICG–mediated photothrombosis led to immediate hypoperfusion of the entire PCV network in all 18 cases. Conclusions: By the use of a two–fold dye infusion scheme for conventional ICG angiography, identification of the neovascular network ingrowth site was achieved in 94.7% of the patients with PCV. Studies on the influence of focal treatment at such sites in the natural course of the disease are highly recommended.

Keywords: choroid: neovascularization • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • laser