Simultaneous measurement of cerebral oxygen consumption and blood flow using 17O and 19F magnetic resonance imaging

Abstract

17O and 19F magnetic resonance (MR) imaging were used to determine simultaneously the concentrations of H217O and CHF3 in 0.8-cc voxels in the cat brain during inhalation of a gas mixture containing both 17O2 and CHF3. The arterial time course of CHF3 was determined by "on-line" mass spectrometer detection of expired CHF3, and the arterial time course of H217O was determined by 17O MR analysis of arterial samples withdrawn during the inhalation period. The brain data and the arterial data for the two tracers were combined to calculate the cerebral oxygen consumption (CMRO2) and the CBF. The protocol was repeated on seven cats, using pentobarbital anesthesia. The average values of CMRO2 and CBF for a 0.8-cc voxel in the parietal cortex were 1.5 ± 0.5 mmol kg-1 min-1 and 38 ± 15 ml 100 g-1 min-1, respectively. In individual animals the average uncertainty in CMRO2 and CBF, calculated from Monte Carlo approaches, was ±9%.