Image Analysis of Optical Coherence Tomography Scans to Explore Established and Novel Choroidal Features in Patients With Central Serous Chorioretinopathy

Abstract

Purpose: To explore the characteristics of choroidal tissue in patients with and without central serous chorioretinopathy (CSC) using an automated system of image analysis to determine known and novel metrics.Methods: This was a retrospective case-control analysis of optical coherence tomography scans of patients seen at Manchester Royal Eye Hospital, UK, comparing patients with active CSC to an age-matched and gender-matched group with no CSC using a purpose-built automated system of image analysis. The expert system segments and measures established and novel features of choroid using a combination of thresholding, noise removal, and morphological techniques.Results: A total of 72 patients were included in this study, with 40 included in the group with CSC and 32 patient controls with no CSC. There were significant increases from normal to CSC of median choroidal vascularity index, 54.7(median absolute deviation = 9.8) to 61.2(4.3), and all choroidal thickness indices including maximum depth, from 249.0(90.1) mm to 372.3(80.3) mm. For novel measures, there was a significant increase in tissue entropy from 6.68(0.28) to 6.95(0.17) and area of the largest five vessels from 6.28(3.04) mm 2 to 9.10(3.49) mm 2 . The ratio of vessel lumen to stromal tissue intensity was conversely significantly reduced from 0.674(0.11) in normal patients to 0.59(0.06) in CSC.Conclusion: The automated system of choroidal analysis expands on the utility of known measures and introduces novel metrics. These findings contribute pathophysiological insights and metrics for further assessment and research on conditions affecting choroidal tissue.

Differentiating a pachychoroid and healthy choroid using an unsupervised machine learning approach

“…pachychoroid disease. In addition, different choroidal layers (Haller, Sattler, and choriocapillaris) are discernible with this imaging technique, and various imaging indices have been previously proposed for quantification of vascular dilation in EDI-OCT 3,4 .…”

Choroidal Vascularity Index versus Choroidal Thickness as Biomarkers of Acute Central Serous Chorioretinopathy

“…Several studies have been published regarding CVI as a second potential biomarker of CSCR, representing a ratio of choroidal vessel luminal area to the total choroidal area [2, 11‒16]. In our series, CVI was statistically superior in acute CSCR than in control eyes.…”

“…Nkrumah et al [35] reported higher CVI values (0.7054 ± 0.15) in acute cases of CSCR versus 0.6518 ± 0.2 in healthy control eyes but analyzing only central B-scans. Referred CVI data for healthy control patients have ranged from 0.4940, 0.5130, 0.5470 [11, 15, 21] . In our series, it was 0.4913.…”

“…Kim et al [12] found a CVI of 0.7149 ± 0.215 using the central 1,500 µm in acute CSCR. Aslam et al [11] published 0.612 ± 0.043 using the central 30° of a B-scan. Agrawal et al [13] published values of 0.7054 ± 0.150 in acute CSCR also using the central 1,500 µm.…”

“…Recently, the choroidal vascularity index (CVI) has been proposed as a new biomarker for CSCR [2,6,7,[11][12][13][14][15]. The CVI is understood as the ratio of choroidal vessel luminal area to the total choroidal area [16].…”