Hyperpolarized Noble Gas Mri of the Brain and Lungs

INTRODUCTION We are developing a new diagnostic technology: magnetic resonance imaging (MRI) and spectroscopy of hyperpolarized noble gases. Large non-equilibrium nuclear spin polarizations can be created in the spin-1/2 noble gases, He and Xe, using the technique of spin-exchange optical pumping. Such large polarizations greatly enhance the magnetic resonance detection of He and Xe, enabling high-resolution MRI studies of the lung and airways, as well as dissolved tissue-phase investigations of organs and tissues, such as the brain, using lipophilic Xe. An important feature of hyperpolarized noble gas MR is that it does not require a large magnetic field, unlike the conventional water proton MR method used in medical MRI. Low magnetic field MRI with hyperpolarized noble gases can allow us to use a small, light-weight, low-power devices. This capability provides potential for advances in both portable ground-based and practical space-based MR systems. Our proposed ground-based investigations with hyperpolarized noble gas MR will affect biomedical research in two important ways: (1) by providing the potential to acquire novel information about physiological structure and function of the lung and the brain in space-flight and in terrestrial gravity, and (2) by developing a new diagnostic technology that has clinical applications for diagnosis of pathology.