Biomedical MRI

Principal investigator

Senior researchers & postdocs

Ph.D. students

Overview

Osteoarthritis increasingly causes personal burden and costs to the society with the increasing life expectancy. Magnetic resonance imaging (MRI) and especially quantitative MRI methods are the most sensitive for diagnostics of osteoarthritis. The group investigates a number of different MRI contrasts and imaging methods for the use in diagnostics of articular cartilage and bone disorders, such as OA. Focuses of the research have been in assessing the utility of novel methods, such as quantitative susceptibility mapping (QSM) and different rotating frame of reference relaxation methods, such as adiabatic T1rho and relaxation along a fictituous field (RAFF) for the diagnosis of OA. Most of the research is conducted on ex vivo tissue (bone and cartilage) explants at high magnetic field, 9.4 tesla. To establish the utility and potential of a specific method, a wide variety of reference techniques are applied, to understand in depth what the properties of the tissue explant are and how the new MRI methodology relates to them.

Besides investigating new methods, another focus of the research is in investigating various issues related to different methods, such as the orientation dependence (orientation anisotropy) of the different quantitative MRI methods and the relaxation parameters, with a nice overview given in Hänninen et al, Sci Rep 2017, describing the orientation dependence of a number of quantitative MRI methods in cartilage.

Since articular cartilage, especially the deep layers of cartilage let alone the underlying bone, have extremely rapid T2* relaxation times, the signal of these tissues is quickly lost with traditional MRI methods. Such properties of the tissue call for the use of ultra-short echo time imaging. Methods in the family of “echoless” or zero echo time or ultra-short echo time include for example ZTE (Zero echo time imaging), UTE (Ultra-short echo time imaging) and SWIFT (SWeep Imaging with Fourier Transform). These methods allow depicting all of the tissues in joints.

Follow the links below for the methods.