Quantitative MRI: Magnetic Metrology to Solve Some of the World’s Most Important Problems

Magnetic resonance imaging (MRI) can manipulate and detect spins inside the human body and, when made quantitative (qMRI), can be used to measure many important physiological parameters. We do not usually consider humans to be magnetic, but they are complex and important magnetic systems. Understanding and manipulating spins in humans and biomaterials allow measurements of tumor volumes and properties, neural connectivity, tissue water dynamics, tissue electromagnetic and mechanical properties, local temperature, local metabolic and neurotransmitter concentrations, and the absorption and propagation of microwave and X-ray radiation. Since its development over 50 years ago by physicists and engineers, MRI has developed into the premier method to measure properties and functionally inside living systems and biomaterial surrogates, with the ability to do three-dimensional and four-dimensional mapping with sub-millimeter and sub-second resolution. The transition of MRI to qMRI has enabled many new and surprising applications.

I will present recent advances in qMRI that enable the imaging of microwave propagation and absorption in biomaterials using hyperpolarized low-field MRI. We can see how this ubiquitous microwave radiation (from cell phones, WiFi, Bluetooth, etc.) interreacts with the complex electromagnetic structures that exist in humans. I will present new qMRI techniques to map radiation dose from therapeutic X-ray and proton sources used in cancer treatments. I will show how qMRI is used to measure water dynamics and spin-relaxation in tissue to enable in-vivo biopsies, where tissue health can be determined without invasive procedures.