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Transverse relaxivity of particulate MRI contrast media: From theories to experiments
Author(s) -
Muller Robert N.,
Gillis Pierre,
Moiny Francis,
Roch Alain
Publication year - 1991
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.1910220203
Subject(s) - transverse plane , magnetization , nuclear magnetic resonance , particle (ecology) , contrast (vision) , spin echo , particle size , spin (aerodynamics) , gadolinium , particulates , condensed matter physics , materials science , physics , chemistry , magnetic resonance imaging , optics , magnetic field , thermodynamics , radiology , medicine , oceanography , organic chemistry , quantum mechanics , metallurgy , geology
Abstract Computer simulations and experimental approach have been used to characterize the properties of particulate MRI contrast agents with special attention paid to the influence of particle size. Up to approximately 50 nm, an increase of the particle diameter leads to a strong enhancement of the transverse magnetization decay rate. For larger grains or aggregates, the decay rate measured without spin‐echo formation reaches a plateau. When observed through a spin‐echo sequence, the transverse magnetization decay rate becomes slower on increasing the particle size or on shortening the echo time. For these large particles, multiexponential decay rates are observed. Definition and measurement of relaxivity in such systems is discussed. © 1991 Academic Press, Inc.