OCT Angiography-Based Quantitative Choroidal Vasculature Analysis in Choroidal Melanomas and Nevi.

Purpose: Differentiation between choroidal melanoma (CM) and choroidal nevus (CN) is primarily made clinically with the aid of multimodal imaging. Both entities can be distinguished by their vascular architecture in histopathology. OCT angiography (OCT-A) is a noninvasive method to visualize retinal and choroidal vasculature and has rarely been used to differentiate CM and CN, and if so, exclusively descriptively. The purpose of this study was to differentiate both entities via OCT-A using an open-source vascular analysis software (OCTAVA), using quantitative choroidal vasculature analysis. Design: Retrospective case-control study. Subjects: Treatment-naïve patients with CM and CN who obtained OCT-A of the tumor at the University Hospital Essen between November 2022 and December 2024. Methods: Choroidal OCT-A sections were analyzed using an ImageJ-based open-source software (OCTAVA). Main Outcome Measures: To assess the comparison between CM and CN using vessel area density, vessel length density, total vessel length, mean vessel diameter, and tortuosity index. Results: Thirty patients with CM and 30 patients with CN could be included in the study. Choroidal melanoma showed significantly reduced vessel area density (30.46% vs. 37.10%; P < 0.001), vessel length density (1.83% vs. 2.40%; P < 0.001), total vessel length (11.8 vs. 19.7 mm; P < 0.001), and tortuosity index (0.140 vs. 0.155; P = 0.008) compared with CN, whereas vessel diameter showed no significant difference. Receiver operating curve analysis demonstrated good diagnostic performance for vessel area density, vessel length density, and total vessel length (area under the curve: 0.81-0.86). Conclusions: OCT angiography using open-source software quantitative choroidal vasculature analysis may play a future role in objective differentiation between CM and CN. Future role of OCT-A in multimodal imaging for melanocytic choroidal tumors must, however, be further validated in larger, prospective trials and across different, preferably commercially available OCT platforms. Financial Disclosures: The authors have no proprietary or commercial interest in any materials discussed in this article.