Quantification and Temporal Study of Physiologic Lung Changes in Animal Models of Lung Disease Using 2D and 3D-CSI with Xe-12

Jaime Mata¹, Kai Ruppert¹, Isabel Dregely², Talissa Altes¹, G. Wilson Miller¹, Peter Sylvester¹, Stephen Ketel³, Jeff Ketel³, Iulian Ruset³, F. William Hersman³, Klaus Hagspiel¹, James Brookeman¹, John Mugler III¹

We report the preliminary evaluation of an optimized 2D-CSI and 3D-CSI technique with hyperpolarized Xe-129, using a rabbit model of lung fibrosis and another of emphysema. We report also for the first time, the acquisition of multiple contiguous slices images with a 3D-CSI version, that covers the entire lung in ~15s. From the CSI data, we directly calculate images reflecting the amount of Xe-129 in the airspaces, and dissolved in the lung tissue, blood, and other compartments thus obtain detailed spatial information regarding how Xe-129 is distributed in those different compartments, providing regional information about lung physiology. High-resolution 2D-CSI maps of the animal in the lung fibrosis group, show the presence of a third dissolved-phase chemical shift peak at around 185ppm from the alveolar gas peak, and adjacent to the dissolved-phase tissue peak. Quantification of the CSI maps for the animal in the fibrosis model group, show an almost two fold increase in the normalized tissue and blood peaks (tissue/gas and blood/gas). Maps of the 2D-CSI acquisitions for each one of the resolved peaks show that blood and tissue lung maps are identically spatially distributed at 1.5Tesla, perhaps due to signal contamination from their very close spectral proximity at this magnetic field. 2D and 3D-CSI acquisitions at magnetic fields higher than 1.5T should create a larger separation of the chemical shift peaks for each lung compartment and produce more detailed anatomical and physiological information. The single breath-hold 3D-CSI maps presented in here, show a promising development of this technique.