The Presence of Fine Network Component in Indocyanine Green Angiography Predicts the Activity of Polypoidal Choroidal Vasculopathy

Abstract

Purpose: : Polypoidal choroidal vasculopathy (PCV) has a distinctive choroidal appearance characterized by an abnormal branching vascular network with polyp-like structures by indocyanine green angiography (ICGA). We evaluated the angiographic features of PCV networks in association with the activity of the disease.

Methods: : We first of all defined two characteristic vascular components in a typical PCV network as ‘fine network’ and ‘differentiated network’ according to the early phase ICGA; the former is composed of irregularly-structured fine vasculature complex and the latter is composed of branching vessels, often of fan-shaped and of differentiated appearance. We retrospectively studied the medical records of 29 eyes of 29 patients with PCV who had been previously treated with photodynamic therapy (PDT) and had been angiographically followed-up for at least 12 months. We assessed the change in the size of the fine network after PDT and its association with the re-appearance of polyp-like structures or exudative changes as an indicator of PCV activity.

Results: : Before PDT, the fine network component was present in all the eyes except for 5 eyes whose network was invisible due to the masking pigment epithelial detachment. After the first PDT, exudative changes were once more or less resolved in all the cases and the fine network was either reduced in size or disappeared in 23 eyes, in which the differentiated network replaced the fine network component. During the follow up period, 19 eyes exhibited recurrence or enlargement of the fine network, of which 15 eyes simultaneously or successively showed recurrence of polyp-like structures and 17 eyes showed exudative change. In contrast, among the 10 eyes with the absence of the fine network component throughout the post-PDT follow-up period, only 2 eyes developed polyp-like structures without any exudative change.

Conclusions: : The fine network was observed ahead the time of recurrence of poly-like structures or an exudative change. The fine network may be the essential component of active PCV itself.

Keywords: age-related macular degeneration • imaging/image analysis: clinical