Hänninen, N., Rautiainen, J., Rieppo, L., Saarakkala, S., Nissi, M. (2017) Orientation anisotropy of quantitative MRI relaxation parameters in ordered tissue. Scientific Reports, 7 (1), doi:10.1038/s41598-017-10053-2
Orientation anisotropy of quantitative MRI relaxation parameters in ordered tissue
|Author:||Hänninen, Nina1,2; Rautiainen, Jari1; Rieppo, Lassi2,3;|
1Department of Applied Physics, University of Eastern Finland
2Research Unit of Medical Imaging, Physics and Technology, University of Oulu
3Medical Research Center Oulu, Oulu University Hospital and University of Oulu
4Department of Diagnostic Radiology, Oulu University Hospital
|Online Access:||PDF Full Text (PDF, 3 MB)|
|Persistent link:|| http://urn.fi/urn:nbn:fi-fe201709258707
|Publish Date:|| 2017-09-25
In highly organized tissues, such as cartilage, tendons and white matter, several quantitative MRI parameters exhibit dependence on the orientation of the tissue constituents with respect to the main imaging magnetic field (B₀). In this study, we investigated the dependence of multiple relaxation parameters on the orientation of articular cartilage specimens in the B₀. Bovine patellar cartilage-bone samples (n = 4) were investigated ex vivo at 9.4 Tesla at seven different orientations, and the MRI results were compared with polarized light microscopy findings on specimen structure. Dependences of T₂ and continuous wave (CW)-T₁ᵨ relaxation times on cartilage orientation were confirmed. T₂ (and T₂*) had the highest sensitivity to orientation, followed by TRAFF2 and adiabatic T₂ᵨ. The highest dependence was seen in the highly organized deep cartilage and the smallest in the least organized transitional layer. Increasing spin-lock amplitude decreased the orientation dependence of CW-T1ρ. T₁ was found practically orientation-independent and was closely followed by adiabatic T₁ᵨ. The results suggest that T₁ and adiabatic T₁ᵨ should be preferred for orientation-independent quantitative assessment of organized tissues such as articular cartilage. On the other hand, based on the literature, parameters with higher orientation anisotropy appear to be more sensitive to degenerative changes in cartilage.
|Type of Publication:||
A1 Journal article – refereed
|Field of Science:||
3126 Surgery, anesthesiology, intensive care, radiology
Financial support from the Academy of Finland (grants #285909, #293970, #297033, #268378 and #303786) and the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement no. 336267 are gratefully acknowledged.
|Academy of Finland Grant Number:||
285909 (Academy of Finland Funding decision)
293970 (Academy of Finland Funding decision)
297033 (Academy of Finland Funding decision)
303786 (Academy of Finland Funding decision)
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