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Effect of induced field inhomogeneity on transverse proton NMR relaxation in tissue water and model systems
Author(s) -
Kurland Robert J.,
Ngo Frank Q. H.
Publication year - 1986
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910030307
Subject(s) - proton , transverse plane , nuclear magnetic resonance , relaxation (psychology) , field (mathematics) , materials science , physics , nuclear physics , anatomy , mathematics , medicine , pure mathematics
The effect of induced field inhomogeneity (IFI) on transverse NMR relaxation of water protons in tissue has been investigated by examining the field dependence of the effective transverse relaxation rates (1/ T 2 eff) for in vitro canine brain tissue samples. At fields of 0.47, 2.35, 7.05 T (corresponding to 20, 100, and 300 MHz, respectively) the transverse relaxation rates for both white and gray matter samples follow a field dependence of the form 1/ T 2 eff = C 0 + C 1 B 0 , where B 0 is the applied field. The linearly dependent term, C 1 B 0 , which reflects the IFI contribution, does not contribute much (i. e., less than 20%) at fields less than 2.0 T. However, at greater field strengths the contribution is appreciable, e. g., greater than 60% at 7.0 T. Results from model systems of glass beads are also reported to illustrate IFI effects. For both the model systems and canine brain tissue samples, the effects of restricted diffusion are qualitatively evident in Hahn spin‐echo experiments. © 1986 Academic Press, Inc.