Repeatability of Choroidal Thickness Measurements on Enhanced Depth Imaging Optical Coherence Tomography Using Different Posterior Boundaries

Abstract

PURPOSE To assess the reliability of manual choroidal thickness measurements by comparing different posterior boundary definitions of the choroidal-scleral junction on enhanced depth imaging optical coherence tomography (EDI-OCT). DESIGN Reliability analysis METHODS Two graders marked the choroidal-scleral junction with segmentation software using different posterior boundaries: 1) the outer border of the choroidal vessel lumen, 2) the outer border of the choroid stroma, and 3) the inner border of the sclera, to measure the vascular choroidal thickness (VCT), stromal choroidal thickness (SCT), and total choroidal thickness (TCT), respectively. Measurements were taken at 0.5 mm intervals from 1.5 mm nasal to 1.5 mm temporal to the fovea, and averaged continuously across the central 3 mm of the macula. Intraclass correlation coefficient (ICC) and coefficient of reliability (CR) were compared to assess intergrader and intragrader reliability. RESULTS Choroidal thickness measurements varied significantly with different posterior boundaries (P = <0.001 for all). Intergrader ICCs were greater for SCT (0.959 – 0.980) than TCT (0.928 – 0.963) and VCT (0.750 – 0.869), even in eyes where choroidal-scleral junction visibility was <75%. Intergrader CRs were lower for SCT (41.40 – 62.31) than TCT (61.13 – 74.24) or VCT (72.44 – 115.11). ICCs and CRs showed greater reliability for averaged VCT, SCT, or TCT measurements, than at individual locations. Intragrader ICCs and CRs were comparable to intergrader values. CONCLUSIONS Choroidal thickness measurements are more reproducible when measured to the border of the choroid stroma (SCT) than the vascular lumen (VCT) or sclera (TCT).

Elevated Choroidal Thickness and Central Serous Chorioretinopathy in the Fellow Eyes of Patients with Circumscribed Choroidal Hemangioma

“…Several authors have reported that EDI-OCT images are not as clear in patients with a thickened choroid [12, 21]. Specifically, it is more difficult to discern the distal boundary of the choroid at the choroid-sclera junction when the choroid is thickened [12].…”

“…Specifically, it is more difficult to discern the distal boundary of the choroid at the choroid-sclera junction when the choroid is thickened [12]. In this study, CT was measured in the subfoveal space from the outer surface of the RPE to the proximal edge of the hyperreflective band at the choroid-sclera junction.…”

“…CT was defined as the distance from the posterior side of the hyperreflective band of the retinal pigment epithelium (RPE) to the choroid stroma at the choroid-sclera junction. The choroid stroma was selected as the distal boundary for CT measurements based on recent evidence that this boundary provides the most reliable CT measurements [12]. Signs of CSCR were defined as serous pigment epithelial detachments or RPE/ellipsoid zone disruptions observed on spectral-domain OCT images (Fig.…”

Macular Fluid Reduces Reproducibility of Choroidal Thickness Measurements on Enhanced Depth Optical Coherence Tomography

“…Recent studies suggest that the repeatability of CT measurements may be optimized at the stromal border. 16 These factors all serve to make CT estimation imprecise, necessitating reproducibility studies to guide analysis.…”

“…Most studies to date have assessed CT measurement repeatability in healthy eyes, 16–23 with a few studies examining CT in diabetic retinopathy and AMD. 15,24–27 We hypothesize that the reliability of CT measurements may be less determined by the pathophysiology of particular conditions, than by the type or quantity of overlying retinal fluid in the macula.…”