Phenotypic Differences of Punctate Inner Choroidopathy (PIC) and Multifocal Choroiditis (MFC) Utilizing Fluorescence Lifetime Imaging Ophthalmoscopy (FLIO)

Abstract

Purpose : Punctate inner choroidopathy (PIC) and multifocal choroiditis (MFC) are two white dot syndromes that share common clinical features such as choroidal neovascularization (CNVM), cystoid macular edema (CME), intraocular inflammation, and retinal atrophy. This study investigates phenotypic differences between these two inflammatory diseases utilizing fluorescence lifetime imaging ophthalmoscopy (FLIO).

Methods : 8 eyes of 8 patients with PIC and 6 eyes of 6 patients with MFC (mean age 40 ± 18 years) and 14 age-matched healthy subjects were investigated in this study. FLIO images of a 30° retinal field at the foveal center were acquired using a prototype Heidelberg Engineering Spectralis-based FLIO. In all patients, FLIO lifetimes were recorded in short (498-560 nm, SSC) and long (560-720 nm, LSC) spectral wavelength channels, with mean autofluorescence lifetimes (tm) calculated and analyzed. In addition, FLIO lifetimes from PIC and MFC-specific lesions were obtained and compared in both spectral channels.

Results : FLIO can discriminate between PIC and MFC based on phenotypic differences in FLIO lifetimes from both spectral channels. While MFC lesions have consistently prolonged of lifetimes in both channels, PIC lesions show heterogeneity of long and short lifetimes in the SSC and LSC, respectively. Some PIC lesions with long FLIO lifetimes in the SSC emit short FLIO lifetimes in the LSC. Collectively, FLIO lifetimes are prolonged in MFC and PIC compared to age-matched controls in the outer ring of the posterior pole in the LSC (240 ps versus 194 ps, p<0.05).

Conclusions : FLIO proves to be a promising imaging modality that offers a possibility to differentiate between PIC and MFC. The lifetime heterogeneity seen in PIC and significantly prolonged lesion lifetimes of MFC patients may provide additional diagnostic tools as well as insight into disease-specific mechanisms, activity, and progression.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.

 

Fundus autofluorescence (FAF) intensity images and FLIO lifetimes in MFC and PIC patients compared to a healthy age-matched control. FLIO lifetimes are shown in the short (498-560 nm, SSC) and long (560-720 nm, LSC) spectral channels.