Three-dimensional quantification of structural changes in central serous chorioretinopathy using optical coherence tomography

Abstract

Purpose : To quantify retinal and choroidal structural changes volumetrically in eyes with central serous chorioretinopathy (CSCR) during follow up visits.

Methods : Fovea-centered, wide-field (12×12-mm), high-density (1024×1024 A-lines) 3-D retinal images were acquired using a commercial swept-source optical coherence tomography (SS-OCT) (PLEX® Elite 9000, Carl Zeiss Meditec Inc., Dublin, CA). To three-dimensionally align the OCT scans from baseline and follow-up sessions, an improved automated volumetric registration algorithm was developed which performs non-rigid registration in the lateral direction and rigid registration in the axial direction. After that, a voxel-wise reflectance comparison between the registered volumes was calculated to highlight the structural difference such as subretinal fluid (SRF), layer displacement and thickness change (Figure 1) during follow up visits. The voxels with values that were greater than 97.5 percentile in the normal control were defined as change voxels for the calculation of structural change volumes in the retina and choroid. Wilcoxon rank-sum tests were used to determine the significance of the detected structural changes between the observational and treatment groups.

Results : Ten eyes from CSCR patients (n=6, age range: 26-60 years) and four eyes from healthy volunteers (n=2, age range: 28-39 years) were included in this retrospective study. The effectiveness of the volumetric registration was confirmed by the significantly improved Jaccard coefficients (CSCR: 0.27 ± 0.11 vs. 0.83 ± 0.01, P<0.001; Healthy Subjects: 0.25 ± 0.07 vs. 0.84 ± 0.01, P<0.001) of superficial vascular complexes large vessel masks, as well as the negligible (1.94 ± 2.06 µm) axial difference of center of mass for OCT A-lines from registered baseline and follow-up scans in healthy eyes. The structural changes of CSCR eyes in follow up scans were significantly greater in the treatment group than that in the observational group (Total region: 29.28 ± 16.72 mm³ vs. 0.93 ± 1.08 mm³, P<0.01; Retina region: 18.70 ± 9.99 mm³ vs. 0.61 ± 0.67 mm³, P<0.01; Choroid region: 10.58 ± 7.04 mm³ vs. 0.32 ± 0.41 mm³, P=0.03).

Conclusions : The volumetric registration algorithm can confidently detect and quantify 3-D map of morphological changes in CSCR, which might be useful for tracking the progression, treatment response, and possibly recurrence for CSCR patients.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.