The influence of oxygenation on the 19F spin-lattice relaxation rates of fluosol-DA

The spin-lattice relaxation rates (1/T1) were measured at 94.1 MHz for six peaks in the 19F NMR spectrum of the perfluorochemical blood substitute fluosol-DA, which contains a mixed emulsion of perfluorodecalin and perfluorotripropylamine. Each of these rates increased linearly with the percentage of oxygen dissolved in the emulsion. Relative values of the linear increase for different peaks established that, for perfluorotripropylamine in the mixed emulsion, the oxygen-fluorocarbon interaction is loosely but preferentially oriented in a manner similar to that previously established for other pure fluorocarbons. The uncertainty in the oxygen level estimated from T1 measurements is somewhat less than 5% O2 and it is thus established that quantitative non-invasive oxygenation measurements can be made to sufficient precision by this approach, using fluosol-DA and 19F spin-lattice relaxation.