Magnetic resonance imaging (MRI) is known for exquisite in vivo imaging of soft tissue anatomy and physiological function. Magnetization transfer (MT) MRI is a family of specialty techniques that provide a special window on tissue composition and microstructure. MT is a phenomenon by which MRI-visible hydrogen protons (primarily associated with water molecules) interact with other hydrogen nuclei that are not MRI-visible. These latter protons reside in macromolecules bound to membrane or tissue microstructure and experience restricted motion. This interaction can be exploited to produce a distinct MRI contrast. MT-MRI has had applications in many organs and biological tissues, including the brain and the musculoskeletal (MSK) system. MT-MRI of musculoskeletal tissue dates back to the early beginnings following the discovery of the MT effect. In this presentation, we will review the physical underpinnings of MT-MRI, the main techniques, quantitative advances, and notable clinical applications.
Magnetization transfer (MT) is a phenomenon that leads distinct contrast mechanism in MRI that exploits the interaction between MRI-visible protons (water) and MRI-invisible protons (restricted macromolecules)
Basic MT contrast can be achieved using widely-available pulse sequences that selectively affect the magnetization of MRI-invisible protons, which in turn alters the MRI signal
Indirect imaging of the restricted macromolecules in tissue can be useful in characterizing MSK tissues—such as cartilage—and the brain
Ives Levesque, PhD, is a medical physicist at the McGill University Health Centre (MUHC), and Assistant Professor of Oncology in the McGill Medical Physics Unit. Prof. Levesque is an expert in the development of methods in magnetic resonance imaging (MRI), and in quantitative imaging. His current research interests include contrast-enhanced perfusion, diffusion, magnetization transfer, and susceptibility mapping. Prof. Levesque is a graduate of the Medical Physics program at McGill University (2009) and was a postdoc in Electrical Engineering and Radiology at Stanford University (2010-2013). In 2011 he was named a Junior Fellow of the ISMRM. His group’s research is funded by NSERC, CIHR, and the Research Institute of the MUHC.