Hydrogen/fluorine retuning tomography. applications to ¹h image‐guided volume‐selective ¹⁹f spectroscopy and relaxometry of perfluorocarbon emulsions in tissue

TLDR

The study develops a hardware modification and pulse sequences that enable recording of 19F images, spectra, and relaxation times using a 1H tomography bird‑cage resonator. The HYFY technique retunes the resonator between 1H and 19F, permitting identical slices to be localized with proton imaging and then interrogated with fluorine MR through volume‑selection methods. The method was validated on phantom samples and excised porcine organs perfused with perfluorocarbon emulsions, showing that frequency switching can be performed without removing the specimen.

Abstract

A hardware modification which permits the record of 19F images, spectra, and relaxation times with a 1H tomography bird-cager resonator is described. Changing the spectrometer frequency from 1H to 19F resonance and vice versa is possible without removing the object to be investigated. This hydrogen/fluorine retuning tomography (HYFY) technique permits studies of identical slices or volume elements with 1H as well as with 19F resonance. In particular, it is possible to localize volume elements on the basis of multislice proton images and then to investigate these volume elements with fluorine magnetic resonance by the aid of volume selection methods. For this purpose, pulse sequences for the localized and spectroscopically resolved determination of spin-lattice and transverse relaxation times have been developed. The applicability of the techniques has been demonstrated by the aid of phantom samples as well as with excised porcine organs which have been perfused with perfluorocarbon emulsions.