Meeting Banner
Abstract #3127

Characterizing Microstructure by a Time-Dependent Transverse Relaxation Rate

Alexander Ruh1, Philipp Emerich1, Dmitry S. Novikov2, Valerij G. Kiselev1

1Department of Radiology, Medical Physics, University Medical Center Freiburg, Freiburg, Germany; 2Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, United States

The correlation time of diffusing spins in magnetically heterogeneous tissues is often commensurate with the timing of MRI experiments. This results in a time dependent transverse relaxation rate that for long times approaches the monoexponential limit. Here we show that the power law of this approach represents the statistics of large-scale organization of magnetic microstructure. The origin of this effect is the self-averaging, which is inherent to diffusion narrowing, when spins are exploring microstructure via diffusion. The present results enable an analysis scheme alternative to a previously proposed spectral domain approach, which enlarges options for future quantifications.

Abstract PDF Presentation Video

Keywords

according agreement agrees analytical approaches artificial asymptote averaging behavior behind biological biomedical blood broadens causing cells central characterizes characterizing classes coarse coincides colored commensurate complexity consider considerations constant correlation dashed decay decreasing dependence dependent depicted derivative described determined deviation diffusing diffusion dimensional dimensions disorder domain doped dynamics effective effectively ellipsoids enable energy exact exponent exponential expressions extracellular fact finding fitting fluctuations formal frequency function good heterogeneous identical identification increasing induces infinitely integration interactions iron kernel known lattice length limit liquid long macroscopically major maximally measure measured medical medicine medium micrometers molecular molecules narrowing numerical objects offset organization origin original packing part particular past perfectly perturbation phys physics picture placed positioned positions possess possibilities precession previously proposed qualitative quantifying radiology random randomly refer regular relate sample scale school self shape shuffled simulations spatial spectral spins statistics strength structural structure susceptibility temporal terms theorem though transverse types typical uniform validates variance verified vessels