In vivo 19F-NMR spectroscopic study of halothane uptake in rabbit brain.

Uptake of a fluorinated anesthetic, halothane, in rabbit brain and blood was studied using 19F-NMR spectroscopic techniques. Localized one-dimensional chemical shift imaging and non-localized one-pulse sequence were used to measure brain uptake kinetics in vivo. Halothane signal was found predominantly in the cerebral cortex. Uptake in the brain followed a first-order biexponential kinetics. The average half-lives were 4 min and 70 min, respectively, for the 'fast' and 'slow' phases of the uptake. Uptake in the arterial blood was also biexponential. However, equilibration of halothane in the brain considerably lagged behind that in arterial blood. This delay was ascribed to a 'restricted diffusion' of the anesthetic molecule into brain tissue.