Transverse NMR relaxation as a probe of mesoscopic structure.
Transverse NMR relaxation in a macroscopic sample is shown to be extremely sensitive to the structure of mesoscopic magnetic susceptibility variations. Such a sensitivity is proposed as a novel kind of contrast in the NMR measurements. For suspensions of arbitrary-shaped paramagnetic objects, the transverse relaxation is found in the case of a small dephasing effect of an individual object. Strong relaxation rate dependence on the objects' shape agrees with experiments on whole blood. Demonstrated structure sensitivity is a generic effect that arises in NMR relaxation in porous media, biological systems, as well as in kinetics of diffusion limited reactions.
Kiselev
Valerij G
VG
Section of Medical Physics, University Hospital Freiburg, D79106 Freiburg, Germany. kiselev@ukl.uni-freiburg.de
Novikov
Dmitry S
DS
D004058:Diffusion; D004912:Erythrocytes / Q000737:chemistry; D006801:Humans; D008962:Models, Theoretical; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*