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detection of expired CHF₃, and the arterial time course of H₂¹⁷O was determined by ¹⁷O MR analysis of arterial samples withdrawn during the inhalation period.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%.