QUANTITATIVE MAGNETIC-RESONANCE-IMAGING OF CAPILLARY WATER PERMEABILITY AND REGIONAL BLOOD-VOLUME WITH AN INTRAVASCULAR MR CONTRAST AGENT

A novel method is presented to simultaneously measure the permeability surface area product of water (PS), also known as capillary diffusion capacity, and the regional blood volume (REV). It is based on magneti c resonance imaging of the longitudinal relaxation times of tissue and blood at different concentrations of an intravascular MR contrast age nt. PS and REV were measured in vivo in different regions of the brain and the skeletal muscle of the rat. The average PS values (n = 5) obt ained in cerebral cortex, corpus callosum, hippocampus, thalamus, jaw muscle, and tongue muscle were 3.31 +/- 0.20, 1.81 +/- 0.25, 3.37 +/- 0.36, 3.68 +/- 0.44, 10.6 +/- 1.1, and 14.1 +/- 2.51 ml.min(-1).g(-1), respectively. The corresponding average REV values were 1.63 +/- 0.18 , 1.22 +/- 0.25, 3.30 +/- 0.37, 3.03 +/- 0.36, 1.66 +/- 0.30, and 1.38 +/- 0.33 ml.100g(-1). These results are in good agreement with previo usly reported literature values obtained by means of autoradiography.