Characterization of the Inflammatory Lesions of Multifocal Choroiditis with Spectral-Domain Optical Coherence Tomography and Fundus Autofluorescence Imaging

Abstract

 

Purpose:

 

To characterize with high-definition spectral domain optical coherence tomography (SD-OCT) and fundus autoflourescence (FAF) imaging the various modes of expression seen in multifocal choroiditis, an inflammatory disease that has a high risk of secondary choroidal neovascularization.

 

Methods:

 

This was a retrospective review of consecutive patients with MFC examined in a large group retina practice based in New York City. All patients underwent eye-tracked SD-OCT scanning and FAF imaging at baseline and follow-up. The abnormalities seen with these imaging modalities were correlated with ophthalmoscopic and angiographic findings.

 

Results:

 

There were 44 eyes of 27 patients evaluated. The acute inflammatory lesions of multifocal choroiditis appeared as mounds of homogeneous hyperreflective material immediately under the retinal pigment epithelium (RPE) using SD-OCT imaging. These same lesions had surrounding hyperautofluorescent edges with FAF imaging. In many lesions, the material appeared to erode through the RPE and infiltrated into the overlying outer retina. Choroidal thickening, loss of underlying choroidal vascular detail or both were evident below the site of sub-RPE inflammation only in select lesions. Many of the sub-RPE lesions had no observable associated choroidal abnormality. Some of the sub-RPE lesions resolved both with and without treatment, leaving behind intact retina or foci of outer retinal atrophy with corresponding hypo-autofluorescence on FAF. Other sub-RPE lesions appeared to evolve into choroidal neovascularization that, unlike the acute lesions, contained material that had heterogeneous reflectivity. These lesions often progressed to fibrosis and loss of the overlying photoreceptors as seen with SD-OCT and reactive changes in the involved RPE appearing as altered FAF patterns. Recurrences of inflammatory activity caused a reappearance of the sub-RPE lesions at sites of prior inflammation.

 

Conclusions:

 

The sub-RPE space is a major site of inflammation for what is called multifocal choroiditis. SD-OCT, together with FAF, appears useful for characterizing the various lesions seen in multifocal choroiditis and helping to identify disease activity and response to treatment, as well as improving our understanding of the underlying disease pathogenesis.

 

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)