University of Oulu

Nykänen O, Rieppo L, Töyräs J, et al. Quantitative susceptibility mapping of articular cartilage: Ex vivo findings at multiple orientations and following different degradation treatments. Magn Reson Med. 2018;80:2702–2716.

Quantitative susceptibility mapping of articular cartilage : ex vivo findings at multiple orientations and following different degradation treatments

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Author: Nykänen, Olli1; Rieppo, Lassi2,3; Töyräs, Juha1,4;
Organizations: 1Department of Applied Physics, University of Eastern Finland
2Research Unit of Medical Imaging, Physics and Technology, University of Oulu
3Medical Research Center Oulu, University of Oulu and Oulu University Hospital
4Diagnostic Imaging Center, Kuopio University Hospital
5Department of Diagnostic Radiology, Oulu University Hospital
6Department of Medical Physics & Biomedical Engineering, University College London (UCL)
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.3 MB)
Persistent link:
Language: English
Published: John Wiley & Sons, 2018
Publish Date: 2019-01-30


Purpose: We investigated the feasibility of quantitative susceptibility mapping (QSM) for assessing degradation of articular cartilage by measuring ex vivo bovine cartilage samples subjected to different degradative treatments. Specimens were scanned at several orientations to study if degradation affects the susceptibility anisotropy. T2*‐mapping, histological stainings, and polarized light microscopy were used as reference methods. Additionally, simulations of susceptibility in layered geometry were performed.

Methods: Samples (n = 9) were harvested from the patellae of skeletally mature bovines. Three specimens served as controls, and the rest were artificially degraded. MRI was performed at 9.4T using a 3D gradient echo sequence. QSM and T2* images and depth profiles through the centers of the samples were compared with each other and the histological findings. A planar isotropic model with depth‐wise susceptibility variation was used in the simulations.

Results: A strong diamagnetic contrast was seen in the deep and calcified layers of cartilage, while T2* maps reflected the typical trilaminar structure of the collagen network. Anisotropy of susceptibility in cartilage was observed and was found to differ from the T2* anisotropy. Slight changes were observed in QSM and T2* following the degradative treatments. In simulations, anisotropy was observed.

Conclusions: The results suggest that QSM is not sensitive to cartilage proteoglycan content, but shows sensitivity to the amount of calcification and to the integrity of the collagen network, providing potential for assessing osteoarthritis. The simulations suggested that the anisotropy of susceptibility might be partially explained by the layered geometry of susceptibility in cartilage.

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Series: Magnetic resonance in medicine
ISSN: 0740-3194
ISSN-E: 1522-2594
ISSN-L: 0740-3194
Volume: 80
Issue: 6
Pages: 2702 - 2716
DOI: 10.1002/mrm.27216
Type of Publication: A1 Journal article – refereed
Field of Science: 3111 Biomedicine
3126 Surgery, anesthesiology, intensive care, radiology
Funding: The authors gratefully acknowledge financial support from the Academy of Finland (grants #285909, #293970, #312343) and the Finnish Cultural Foundation, North Savo Regional fund.
Academy of Finland Grant Number: 285909
Detailed Information: 285909 (Academy of Finland Funding decision)
293970 (Academy of Finland Funding decision)
312343 (Academy of Finland Funding decision)
Dataset Reference: Supporting information:
Copyright information: © 2018 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.