Our laboratory is interested in developing new methodologies for magnetic resonance imaging and spectroscopy to increase sensitivity and contrast specificity. A strong emphasis is placed on understanding the physics of MRI hardware and contrast generation, as well its biomedical imaging applications.
Nuclear Spin Hyperpolarization
Nuclear Spin hyperpolarization is used in magnetic resonance as a mean to enhanced the signal from nuclear spins that otherwise will remain undetectable. There are several ways to increase nuclear spin polarization. In the case of nobel gases this is most commonly achieved by spin-exchange optical pumping (SEOP), whereby circularly polarized (laser) light is used to optically pump and spin-polarize valence electrons of an alkali-metal vapor. Through the hyperfine interaction, spin polarization is then transferred from the electrons of the alkali metal to the nuclei of the nobel gas. Applications of spin-polarized Nobel gases range from physics, chemistry, material science, and biomedical imaging. Our lab is interested in the physics of SEOP as well as on its biomedical imaging applications. For additional information on spin exchange optical pumping techniques and its application you can read this review article.
Investigation of non-linear spin dynamics from dipolar-dipolar field interactions
At high magnetic fields, non-linear NMR effects contribute significantly to the detected signal from highly polarized samples (such as humans at normal clinical field strength, which consist of more than 70% water). Theoretically, these effects can be explained classically by the action of the Distant Dipolar Field (DDF) or, quantum mechanically, by intermolecular multiple-quantum coherences (iMQC). These coherences have special properties, such as insensitivity to local magnetic field inhomogeneities and high sensitivity to tissue structure. These signals are used in our Lab to enhance MR image contrast and/or to improve spectral resolution in NMR spectroscopy.
Low and ultralow field MRI
MRI at ultralow field is a rapidly developing area of research that has the potential to revolutionize medical imaging. Unlike traditional MRI, which operates at high magnetic fields of several tesla, ultralow field MRI operates at magnetic fields of only a few millitesla. This has several advantages, including lower costs and reduced safety concerns. However, one of the challenges of ultralow field MRI is that it typically requires longer scan times and lower signal-to-noise ratios compared to high field MRI. This is because the signal from the spins is weaker at lower fields, and the contrast between different tissues is lower. One approach to addressing this challenge is to combine ultralow field MRI with nuclear spin hyperpolarization techniques. Overall, ultralow field MRI and nuclear spin hyperpolarization are two powerful techniques that have the potential to be combined to produce high-quality, low-cost medical images.