Semi-automated International Cartilage Repair Society scoring of equine articular cartilage lesions in optical coherence tomography images

• Published in: Equine veterinary journal Vol. 49; no. 4; p. 552
• Main Authors: Te Moller, N C R, Pitkänen, M, Sarin, J K, Väänänen, S, Liukkonen, J, Afara, I O, Puhakka, P H, Brommer, H, Niemelä, T, Tulamo, R-M, Argüelles Capilla, D, Töyräs, J
• Format: Journal Article
• Language: English
• Published: United States 01.07.2017
• Subjects: Animals; Cartilage Diseases - pathology; Cartilage Diseases - veterinary; Cartilage, Articular - pathology; Horse Diseases - pathology; Horses; Reproducibility of Results; Tomography, Optical Coherence - methods; Tomography, Optical Coherence - veterinary; horse; interobserver agreement; arthroscopy; chondral defect
• ISSN: 2042-3306
• DOI: 10.1111/evj.12637

Arthroscopic optical coherence tomography (OCT) is a promising tool for the detailed evaluation of articular cartilage injuries. However, OCT-based articular cartilage scoring still relies on the operator's visual estimation. To test the hypothesis that semi-automated International Cartilage Repair Society (ICRS) scoring of chondral lesions seen in OCT images could enhance intra- and interobserver agreement of scoring and its accuracy. Validation study using equine cadaver tissue. Osteochondral samples (n = 99) were prepared from 18 equine metacarpophalangeal joints and imaged using OCT. Custom-made software was developed for semi-automated ICRS scoring of cartilage lesions on OCT images. Scoring was performed visually and semi-automatically by five observers, and levels of inter- and intraobserver agreement were calculated. Subsequently, OCT-based scores were compared with ICRS scores based on light microscopy images of the histological sections of matching locations (n = 82). When semi-automated scoring of the OCT images was performed by multiple observers, mean levels of intraobserver and interobserver agreement were higher than those achieved with visual OCT scoring (83% vs. 77% and 74% vs. 33%, respectively). Histology-based scores from matching regions of interest agreed better with visual OCT-based scoring than with semi-automated OCT scoring; however, the accuracy of the software was improved by optimising the threshold combinations used to determine the ICRS score. Images were obtained from cadavers. Semi-automated scoring software improved the reproducibility of ICRS scoring of chondral lesions in OCT images and made scoring less observer-dependent. The image analysis and segmentation techniques adopted in this study warrant further optimisation to achieve better accuracy with semi-automated ICRS scoring. In addition, studies on in vivo applications are required.