Researchers Test Imaging Techniques for Visualizing Subretinal Fibrosis

Multicolor (MC) imaging is better able to detect and analyze subretinal fibrosis and its morphological features in late neovascular age-related macular degeneration (nAMD) compared with color fundus photography (CFP) and ultra-widefield color fundus photography (UWFCP), researchers found in a study published in Retina.

In this study, the first to analyze differences between these imaging modalities, researchers evaluated 32 eyes of 31 patients with fibrotic scars secondary to nAMD. Two graders calculated the area of the fibrosis and assigned integers from 0 to 3 to describe their ability to visualize fibrosis, its margins and distinction from surrounding atrophy with each imaging modality. They differentiated lesions on spectral-domain optical coherence tomography (SD-OCT) and CFP and compared their aspect and characteristics with the MC and UWFCFP. Additional pigment was found within or on the border of the fibrotic scar in 20 eyes. Another 15 had surrounding atrophy, 2 had hemorrhages and 10 had no additional features.

MC allowed for a score 3 (fully visible) for fibrosis visualization in 87.5% of cases while CFP and UWFCFP allowed for that score in 50% of cases (P =.0005). Inter-reader agreement, evaluated with Cohen’s kappa test, was excellent for MC and good for CFP and UWFCFP, while intra-reader agreement was good for all 3 imaging techniques.

MC allowed for a score 3 for fibrosis’ margins in 40.6% of cases while CFP allowed for 15.6% of cases (P =.0078) and UWFCFP in 9.4% of cases (P =.002). Inter-reader agreement was consistent across the 3 imaging modalities, and intra-reader agreement was good across the 3 modalities.

Atrophy was fully visible in all 15 eyes using MC compared with 13.4% of cases with CFP (P =.0002) and 33.3% of cases with UWFCFP (P =.002). Inter-reader agreement was 100% for MC and good for both CFP and UWFCFP, while intra-reader agreement was good for CFP and for UWFCFP and unevaluatable for MC (P <.0001 for all).

The average area of the fibrotic lesions was approximately 14.59 mm² for MC, 13.84 mm² for CFP, and 13.76 mm² for UWFCFP. Reader measurements were consistent, as the intraclass correlation coefficient (ICC) for inter-reader measurements was 0.99 for MC, 0.86 for CFP, and 0.96 for UWFCFP. For intra-reader agreement, the ICC was 0.99 for MC, 0.98 for both CFP and UWFCFP.

 “Therefore, MC imaging, which turns out to be valuable when area measurements are required (better visualization of atrophic and fibrotic boundaries), may be used as a complementary tool for the visualization and diagnosis of subretinal fibrosis, in combination with other imaging modalities, to provide a more detailed and accurate information about the fibrotic scar, as well as other associated findings in late nAMD,” the research shows.

Limitations of the study included the scores being based on subjective evaluation.

Reference

De Rosa I, Ohayon A, Semoun O, et al. Real-color versus pseudo-color imaging of fibrotic scars in exudative age-related macular degeneration. Retina. 2020;40(12): 2277-2284. doi:10.1097/IAE.0000000000002771.