ИСТИНА

Unlike traditional MRI studies based on the registration of NMR signals from hydrogen nuclei (1H, protons), multinuclear MRI approaches deal with nuclei heavier than protons. It is necessary to develop multinuclear MRI due to the need to visualize in vivo living tissues or drugs that do not contain hydrogen atoms introduced into the body. For example, there is a diagnostic need to determine the pathways of circulation and localization in the body of the Perftoran blood substitute introduced into the bloodstream, the molecules of which contain only carbon and fluorine atoms. To visualize it, it is necessary to tune the transmit-receive path of the MRI scanner to the Larmor frequency of fluorine-19. When setting up the scanner for fluorine-19 nuclei, it is possible to solve many important fundamental and applied problems - to visualize the functional tissues of the lungs filled with fluorine-containing gas, to monitor the progress of capsules containing the fluorine preparation along the gastrointestinal tract, to determine (with help recording signals from the corresponding fluorine markers) location of targeted drugs, etc. Fluorine MRI has a number of undoubted advantages - the NMR signal from fluorine-19 nuclei has almost the same intensity as the proton signal; the Larmor frequency of fluorine differs by only 5% from the proton frequency, allowing the use of branded proton coils slightly retuned in frequency. Another significant advantage of MRI on fluorine nuclei is that due to the almost complete absence of fluorine in the body of humans and animals, the fluorine MRI signal from the injected drug is clearly visualized against the zero background of living tissues that do not contain fluorine atoms. Another important task of multinuclear MRI is associated with determining the place of accumulation in the body and measuring the concentration of substances containing sodium-23 nuclei. Deficiency or excess of sodium in the body, primarily NaCl salt, is the cause of widespread socially significant diseases - blood pressure disorders (hyper- or hypotension), diabetes, kidney failure, gallstone pathologies, etc. MRI scanner configured on the resonant frequency of sodium-23 nuclei, allows to non-invasively determine the location of organs with violations of the norm of the sodium concentration in the human body. Using the 23Na-MRI method, one can also solve some important technological problems of measuring, for example, the salinity of canned food products - fish, sausage, salted vegetables. This report presents the results of multinuclear diagnostic studies on fluorine-19 and sodium-23 nuclei, performed using Bruker MRI devices - a medical 0.5-T scanner and a 7-T biospectrotomograph.