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Relaxivity of Gd‐Based MRI Contrast Agents in Crosslinked Hyaluronic Acid as a Model for Tissues
Author(s) -
Fragai Marco,
Ravera Enrico,
Tedoldi Fabio,
Luchinat Claudio,
Parigi Giacomo
Publication year - 2019
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201900587
Subject(s) - gadolinium , relaxometry , relaxation (psychology) , hyaluronic acid , chemistry , macromolecule , mri contrast agent , molecule , nuclear magnetic resonance , ion , magnetic resonance imaging , biophysics , biochemistry , organic chemistry , medicine , psychology , social psychology , genetics , physics , spin echo , biology , radiology
The efficiency of MRI contrast agents depends on the relaxation rate enhancement that they can induce at imaging fields. It is well known that, at these fields, large relaxation rates are obtained by binding of gadolinium(III) ions to large molecules. By the same token, the interaction of the gadolinium(III) complexes with macromolecules that are found in biological tissues can be responsible for an increase of the relaxation rate with respect to the value observed in liquids. We investigate here the relaxation enhancement of gadoteridol (Gd‐HP‐DO3A) in crosslinked hyaluronic acid, taken as model tissue, using fast field‐cycling relaxometry. The analysis of the relaxation profiles as a function of the magnetic fields indicates that a sizable increase in the relaxation rates is due to a modest interaction of the contrast agent with the hydrogel and to the slower mobility of the water molecules outside the first‐coordination sphere of the gadolinium(III) ion.