In vivo MR measurements of regional arterial and venous blood volume fractions in intact rat brain

In vivo measurement of cerebral arterial and venous volume fractions is imp ortant to the understanding of brain physiology and function. By using an i ntravascular perfluorocarbon and F-19 NMR at 4.7 T, regional arterial and v enous volume fractions from an intact rat brain were resolved based on the pseudodiffusion coefficients, which were (33 +/- 7) x 10(-3) and (0.45 +/- 0.13) x 10(-3) mm(2)/sec (mean +/- SD, n = 7) for the fast- and slow-moving component, respectively. By exploiting the linear dependence of the perflu orocarbon F-19 1/T-1 on the dissolved paramagnetic oxygen concentration, co mbined inversion-recovery and diffusion measurements were made to correlate the short T-1 (high-oxygenation) component with the fast-moving component and the long T-1 (low-oxygenation) component with the slow-moving component . The arterial blood volume fraction was 29 +/- 7% of the total cerebral bl ood volume. Finally, experiments were performed in which different oxygen c oncentrations were inhaled to validate this technique. (C) 2000 Wiley-Liss, Inc.