¹⁹F magnetic resonance imaging of cerebral blood flow with 0.4-cc resolution

¹⁹F magnetic resonance imaging techniques were used to determine "wash-in" and "wash-out" curves of the inert, diffusible gas CHF₃ from 0.4-cc voxels in the cat brain, and mass spectrometer gas detection was used to determine the CHF₃ concentration in expired air. These two sets of data were used to calculate cerebral blood flow values in the 0.4-cc voxels, and the blood flow images were registered with high-resolution ¹H magnetic resonance images. Data were collected both during the wash-in and wash-out phases of the experiment, but the two sets of data were analyzed separately to obtain independent estimates of the blood flow during the two phases, i.e., Q_in and Q_out. Repeated determinations of cerebral blood flow images were performed in individual animals, and the entire protocol was repeated on five different animals. The average values of Q_in and Q_out for a typical 0.4-cc voxel in the parietal cortex were 83 ml 100 g^-1 min^-1 and 72 ml 100 g^-1 min^-1, respectively. Monte Carlo calculations utilizing the noise in the ¹⁹F NMR signal from this voxel predict an average standard deviation for Q_in and Q_out of ±10%. The average standard deviation for repeated measurements (in the same animal) of Q_in and Q_out in this voxel was ±14%. We conclude that ¹⁹F magnetic resonance imaging approaches have the potential to image cerebral blood flow in humans.