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

N C R Te Moller; M Pitkänen; J K Sarin; S Väänänen; J Liukkonen; I O Afara; P H Puhakka; H Brommer; T Niemelä; R-M Tulamo; D Argüelles Capilla; J Töyräs

doi:10.1111/evj.12637

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

Equine Vet J. 2017 Jul;49(4):552-555. doi: 10.1111/evj.12637. Epub 2016 Oct 20.

Authors

N C R Te Moller¹, M Pitkänen², J K Sarin^{2

3}, S Väänänen^{2

3}, J Liukkonen², I O Afara⁴, P H Puhakka^{2

3}, H Brommer¹, T Niemelä⁵, R-M Tulamo⁵, D Argüelles Capilla⁵, J Töyräs^{2

3}

Affiliations

¹ Department of Equine Sciences, Utrecht University, Utrecht, the Netherlands.
² Department of Applied Physics, University of Eastern Finland, Kuopio, Finland.
³ Diagnostic Imaging Centre, Kuopio University Hospital, Kuopio, Finland.
⁴ Department of Electrical and Computer Engineering, Elizade University, Ondo, Nigeria.
⁵ Department of Equine and Small Animal Medicine, University of Helsinki, Helsinki, Finland.

PMID: 27592527
DOI: 10.1111/evj.12637

Abstract

Background: 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.

Objectives: 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.

Study design: Validation study using equine cadaver tissue.

Methods: 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).

Results: 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.

Main limitations: Images were obtained from cadavers.

Conclusions: 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.

Keywords: arthroscopy; chondral defect; horse; interobserver agreement.

MeSH terms

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*