Figure 2:

Graph of time course of ¹²⁹Xe signals during injection of ¹²⁹Xe-saline mixture in the tail vein depicts the dynamics of the three resonances corresponding to ¹²⁹Xe in blood (215 ppm), ¹²⁹Xe in plasma or saline (195 ppm), and gaseous ¹²⁹Xe in the airspaces (0 ppm). These resonances are shown in the inset spectrum, which was obtained by averaging the signals from 8 to 12 seconds. These spectral dynamics clearly illustrate that the airspace ¹²⁹Xe peak is dramatically larger (and narrower) than that of the dissolved ¹²⁹Xe resonances and is the most favorable peak for imaging. The dynamics were probed during a 30-second period at a repetition time of 250 msec, with the injection starting at frame 0 and lasting 16 seconds. Arb = arbitrary units, RF = radiofrequency.