University of Oulu

O. Nykänen, J.K. Sarin, J.H. Ketola, H. Leskinen, N.C.R. te Moller, V. Tiitu, I.A.D. Mancini, J. Visser, H. Brommer, P.R. van Weeren, J. Malda, J. Töyräs, M.J. Nissi, T2* and quantitative susceptibility mapping in an equine model of post-traumatic osteoarthritis: assessment of mechanical and structural properties of articular cartilage, Osteoarthritis and Cartilage, Volume 27, Issue 10, 2019, Pages 1481-1490, ISSN 1063-4584,

T2* and quantitative susceptibility mapping in an equine model of post-traumatic osteoarthritis : assessment of mechanical and structural properties of articular cartilage

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Author: Nykänen, O.1; Sarin, J. K.1,2; Ketola, J. H.1,3;
Organizations: 1Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
2Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland
3Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland
4Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
5Institute of Biomedicine, Anatomy, University of Eastern Finland, Kuopio, Finland
6Department of Orthopaedics, University Medical Center Utrecht, Utrecht, The Netherlands
7School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, Australia
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 2.8 MB)
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Language: English
Published: Elsevier, 2019
Publish Date: 2019-11-19


Objective: To investigate the potential of quantitative susceptibility mapping (QSM) and T2* relaxation time mapping to determine mechanical and structural properties of articular cartilage via univariate and multivariate analysis.

Methods: Samples were obtained from a cartilage repair study, in which surgically induced full-thickness chondral defects in the stifle joints of seven Shetland ponies caused post-traumatic osteoarthritis (14 samples). Control samples were collected from non-operated joints of three animals (6 samples). Magnetic resonance imaging (MRI) was performed at 9.4 T, using a 3-D multi-echo gradient echo sequence. Biomechanical testing, digital densitometry (DD) and polarized light microscopy (PLM) were utilized as reference methods. To compare MRI parameters with reference parameters (equilibrium and dynamic moduli, proteoglycan content, collagen fiber angle and -anisotropy), depth-wise profiles of MRI parameters were acquired at the biomechanical testing locations. Partial least squares regression (PLSR) and Spearman’s rank correlation were utilized in data analysis.

Results: PLSR indicated a moderate-to-strong correlation (ρ = 0.49–0.66) and a moderate correlation (ρ = 0.41–0.55) between the reference values and T2* relaxation time and QSM profiles, respectively (excluding superficial-only results). PLSR correlations were noticeably higher than direct correlations between bulk MRI and reference parameters. 3-D parametric surface maps revealed spatial variations in the MRI parameters between experimental and control groups.

Conclusion: Quantitative parameters from 3-D multi-echo gradient echo MRI can be utilized to predict the properties of articular cartilage. With PLSR, especially the T2* relaxation time profile appeared to correlate with the properties of cartilage. Furthermore, the results suggest that degeneration affects the QSM-contrast in the cartilage. However, this change in contrast is not easy to quantify.

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Series: Osteoarthritis and cartilage
ISSN: 1063-4584
ISSN-E: 1522-9653
ISSN-L: 1063-4584
Volume: 27
Issue: 10
Pages: 1481 - 1490
DOI: 10.1016/j.joca.2019.06.009
Type of Publication: A1 Journal article – refereed
Field of Science: 3126 Surgery, anesthesiology, intensive care, radiology
Funding: Support from the Academy of Finland (grants #285909, #293970, and #319440), The Northern Savo Regional Fund of the Finnish Cultural Foundation (grant #65161539), the Finnish Cultural Foundation (grant #00180787) and the Dutch Arthritis Foundation, the Netherlands (grants LLP-12 and LLP-22) are gratefully acknowledged. Help from Mr. Abdul Wahed Kajabi in PLM-imaging is gratefully acknowledged.
Copyright information: © 2019 The Author(s). Published by Elsevier Ltd on behalf of Osteoarthritis Research Society International. This is an open access article under the CC BY license (