Validity of Automated Choroidal Segmentation in SS-OCT and SD-OCT

Abstract

PURPOSE.To evaluate the validity of a novel fully automated three-dimensional (3D) method capable of segmenting the choroid from two different optical coherence tomography scanners: swept-source OCT (SS-OCT) and spectral-domain OCT (SD-OCT). METHODS.One hundred eight subjects were imaged using SS-OCT and SD-OCT. A 3D method was used to segment the choroid and quantify the choroidal thickness along each A-scan. The segmented choroidal posterior boundary was evaluated by comparing to manual segmentation. Differences were assessed to test the agreement between segmentation results of the same subject. Choroidal thickness was defined as the Euclidian distance between Bruch's membrane and the choroidal posterior boundary, and reproducibility was analyzed using automatically and manually determined choroidal thicknesses.RESULTS. For SS-OCT, the average choroidal thickness of the entire 6-by 6-mm 2 macular region was 219.5 lm (95% confidence interval [CI], 204.9-234.2 lm), and for SD-OCT it was 209.5 lm (95% CI, 197.9-221.0 lm). The agreement between automated and manual segmentations was high: Average relative difference was less than 5 lm, and average absolute difference was less than 15 lm. Reproducibility of choroidal thickness between repeated SS-OCT scans was high (coefficient of variation [CV] of 3.3%, intraclass correlation coefficient [ICC] of 0.98), and differences between SS-OCT and SD-OCT results were small (CV of 11.0%, ICC of 0.73). CONCLUSIONS.We have developed a fully automated 3D method for segmenting the choroid and quantifying choroidal thickness along each A-scan. The method yielded high validity. Our method can be used reliably to study local choroidal changes and may improve the diagnosis and management of patients with ocular diseases in which the choroid is affected.

Outer Segment Thickness Predicts Visual Field Response to QLT091001 in Patients withRPE65orLRATMutations

“…In future studies based on volumetric scans, area (2D) and volume (3D) of the preserved retina could be measured aided by improved automated segmentation algorithms with options of manual correction. [30][31][32][33][34] In this study, measurements of OS thickness were conducted manually using a computer program that is not commercially available. However, with improved automated segmentation algorithms with options of manual correction, OS thickness measure could be potentially incorporated into commercial software such as the Heidelberg Eye Explorer (Heidelberg Engineering).…”

Impact of optical coherence tomography scanning density on quantitative analyses in neovascular age-related macular degeneration

“…8 The ability of commercial OCT algorithms to automatically segment retinal boundaries, and generate thickness and volume maps has been very important for its use in clinical practice and in clinical research trials. 9,10 In disorders such as CNV, however, the automatic segmentation boundaries generated by OCT systems are often inaccurate, 9,11,12 likely owing to the extensive outer retinal disruption caused by the disease process. In such cases, the retinal layer boundaries must be manually corrected to assure accurate measurements.…”

“…19 Even newer third-party automated algorithms for CNV lesions require human input and optimization. 11,12 As manual correction of the scans is exhaustive and time consuming, it is unsuitable for regular clinical practice and presents a challenge even in the context of a reading center for clinical trials. 20 Furthermore, many clinicians do not obtain dense volume scans, but less dense sets with only 25-50 B-scans per cube, particularly when using acquisition protocols that utilize extensive B-scan averaging.…”

An Effective Multi-Scales Interpolating and Enhancing Choroidal Vessels Segmentation Method

“…The segmentation schema as show in Figure 2, it is consisted of the RPE surface finding, flattening, getting specific volume, and smoothing, multi-scale Frangi's filtering enhancement [7,8], binary region growing segmentation.…”