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The impact of the relaxivity definition on the quantitative measurement of glycosaminoglycans in cartilage by the MRI dGEMRIC method
Author(s) -
Zheng ShaoKuan,
Xia Yang
Publication year - 2010
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.22169
Subject(s) - gadolinium , chemistry , cartilage , glycosaminoglycan , nuclear magnetic resonance spectroscopy , nuclear magnetic resonance , medicine , anatomy , biochemistry , stereochemistry , physics , organic chemistry
The relaxivities ( R ‐values) of the gadolinium diethylene triamine pentaacetic acid (Gd(DTPA) 2− ) ions in a series of skim‐milk solutions at 0–40% milk concentrations were measured using NMR spectroscopy. The R ‐value was found to be approximately linearly proportional to the concentration of the solid component in the milk solution. Using the R ‐value at 20% solid component (approximately the solid concentration in bovine nasal cartilage), the glycosaminoglycan concentration in bovine nasal cartilage can be quantified using the MRI delayed gadolinium‐enhanced MRI of cartilage method without the customary scaling factor of 2. This finding is also supported by the measurements using 23 Na NMR spectroscopy, 23 Na inductively coupled plasma analysis, and biochemical assay. The choice of the R ‐value definition in the MRI delayed gadolinium‐enhanced MRI of cartilage method is discussed, and the definition of Gd(DTPA) 2− ions as “millimole per volume of tissue (or milk solution for substitution)” should be used. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.