Figure 19.

(A) Nonselective spectra acquired in a mouse as inhaled HXe is distributes throughout the body for progressively longer times. An initially broad, featureless peak is joined by five other distinct contributions over a period of ~8 s. (B) Localizing spectra to different anatomical regions shows that each has a distinct signature, largely due to locally different combinations of water, proteins and lipids, but perhaps also due to local magnetic susceptibility variations. (C) Localized dynamics of signal growth is also distinctive, and highlights how long it takes for pulmonary blood to transport dissolved gases to specific anatomical structures (LV: left ventricle, AA: aortic arch, DA: descending aorta, VC: vena cava, LK: left kidney, RK: right kidney, HW: heart wall, FAT: dorsal adipose deposits). This ranges from <<1 s for oxygenated blood to reach the heart, to >>5 s for gas-exchange to substantially affect dissolved concentrations in lipid-rich tissues on the animal’s back. Reprinted with permission from Loza, et al. (IEEE Trans Med Imaging 2019, ref. [59]).