Estimation of Intrinsic Relaxation Parameters of Human Brain Metabolites in Vivo

Silvia Mangia¹, Michael Garwood¹, Pierre-Gilles Henry¹, Kamil Ugurbil¹, Shalom Michaeli¹

In the present study we estimated the intrinsic relaxation parameters characterizing the dynamics of human brain metabolites (N-Acetylaspartate, NAA, and total-Creatine, t-Cr) from in vivo adiabatic relaxation measurements. The performed simulations relied on few a-priori assumptions regarding known properties of NAA and t-Cr, and were based on the theoretical description of several relaxation channels in the weak field approximation, namely: dipolar interactions, isochronous exchange, anisochronous exchange, and diffusion. Since the intrinsic relaxation parameters are supposed to be sensitive to different functional states, this approach holds great potential to quantitatively assess metabolic processes of interest for biomedical research.