In vivo brain water determination with T1 and T2 measurements

To quantitate brain water noninvasively, the authors have determined the influence of total water content, hydration fraction, and magnetic field strength on observed proton relaxation rates by in vitro and in vivo studies. Several protein solutions of varying water content were used as models of normal and edematous brain for relaxation rate measurements over a range of proton Larmor frequencies. A linear relationship was found for R1 vs the inverse of total water content. A similar result was observed for in vivo studies in which we used an infusion model of edema in the cat (intact blood-brain barrier)