XENON POLARIZATION TRANSFER CONTRAST MRI OF LUNG

We are proposing the development of an MRI pulse sequence package based on the recently invented Xenon Polarization transfer Contrast (XTC) MRI. Upon inhalation of a batch of hyperpolarized 129Xe, the lipophilic xenon dissolves almost instantaneously in the lung tissue and the blood. Although only a small fraction of the gas (ca. 2 percent) is dissolved at any point in time it is nevertheless standing in fast exchange with the much larger gas pool in the air spaces of the lung. Selective destruction of the magnetization of the dissolved 129Xe with the application of a series of frequency selective radio frequency pulses that leave The gas phase magnetization undisturbed makes it possible to encode certain physiological parameters of the parenchyma as intensity variations in the gas phase images The proposed precise characterization of the exchange parameters and their variability in healthy subjects as well as the maximization of the available dynamic range are the key steps for a successful MRI pulse sequence implementation. These results will permit the development of a novel, noninvasive in-viva diagnostic tool that can be sensitized for a range of pathological changes in the lung morphology or function.