Swept-source optical coherence tomography features of choroidal nevi

Abstract

Purpose: To investigate the morphologic characteristics of choroidal nevi using swept-source optical coherence tomography and compare this with enhanced-depth optical coherence tomography.

Design: Retrospective observational case series.

Methods: One choroidal nevus each from 30 eyes of 30 patients was included and received imaging with swept-source OCT (SS-OCT) and enhanced-depth imaging OCT (EDI-OCT). For SS-OCT, a scan acquisition protocol was used involving 12 mm horizontal and vertical scans in the posterior fundus. The main outcome measures were morphologic features of choroidal nevi obtained with SS-OCT imaging. These features were compared to images obtained with EDI-OCT. A 2-tailed Fisher exact test was the statistical method used.

Results: SS-OCT allowed for an appreciation of intralesional details: Of the 30 nevi imaged, intralesional vessels were apparent in 30 (100%), intralesional cavities in 6 (20%), intralesional granularity in 14 (47%), abnormal choriocapillaris in 25 (83%), and abnormal choriocapillaris confined to the tumor apex in 17 (58%). Distended bordering vessels were identified in 22 nevi (73%) and were significantly associated with the presence of previous or persistent subretinal fluid. Intrinsic hyperreflectivity with hyporeflective shadowing was significantly (P = .05) more apparent in 14 of 21 melanotic nevi (67%) compared with 2 of 9 amelanotic nevi (22%). Visualization of the complete nevus-scleral interface was significantly (P = .02) more apparent in 7 of 9 amelanotic nevi (78%) compared with 6 of 21 melanotic nevi (29%), and was not significantly related to tumor thickness (measured by ultrasound) or to tumor configuration. Tumor diameter (but not tumor height) was statistically significantly associated with secondary retinal changes (P = .05) and configuration (P = .01). EDI-OCT was equivalent at determining secondary retinal changes (P = .29), the presence of distended bordering vessels (P = 1), visualization of the nevus-scleral interface (P = .6), and hyporeflective gradation at the nevus-scleral interface (P = .33). However, in melanotic lesions, SS-OCT was significantly superior at visualizing intralesional vessels (P = .0002), intralesional granularity (P = .0005), and abnormal choriocapillaris (P = .0001).

Conclusion: Imaging of choroidal nevi with SS-OCT enables visualization of intralesional details such as vessels (present in 100% of tumors imaged), cavities, and granularity. For melanotic lesions, SS-OCT is significantly better at depicting certain intralesional characteristics compared to EDI-OCT. Distended bordering vessels were recognized in over two thirds of the nevi imaged and were significantly associated with previous or persistent subretinal fluid.