Multinuclear MRI Research.

Abstract

The presented data clearly demonstrate that multinuclear MRI has a great potential in research and clinical fields. The biomedical value of many heavy nuclei that are part of drugs, contrast agents, and molecular complexes in live tissues emphasizes the need for creating and using MRI scanners tuned to the Larmor frequencies of such nuclei. This article discusses a number of specific problems solved with the use of multinuclear MRI. Since the sensitivity of the MRI on heavy nuclei, as a rule, is insufficient for obtaining images of satisfactory quality, it is proposed to use hyperpolarization techniques for preparing objects for the MRI diagnostics. However, bearing in mind the high cost of hyperpolarization techniques, alternative approaches using contrast agents normally absent in tissues can be more suitable in certain situations. For instance, due to the absence of fluorine in the body, 19F MRI allows for successful diagnostics of the respiratory tract and lungs filled with fluorine-containing gas, detecting the location of the blood substitute Perftoran® in the body, monitoring the transport along the gastrointestinal tract of a capsule filled with a preparation containing fluorine-19 nuclei, etc. The possibility of non-invasive local measurements of the concentration of sodium-23 in the body, which, in case of a deviation from the norm, is linked to such pathologies as diabetes, hypertension, renal failure, and many others, is also demonstrated. Reported as well is the creation of transmitting and receiving infrastructure that makes possible effective MRI measurements at low fields (of about 0.5 T) at 10 Larmor frequencies corresponding to the nuclei of hydrogen, deuterium, fluorine, boron, chlorine, sodium, carbon, phosphorus, silicon and oxygen.