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Nondestructive imaging of human cartilage glycosaminoglycan concentration by MRI
Author(s) -
Bashir A.,
Gray M.L.,
Hartke J.,
Burstein D.
Publication year - 1999
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/(sici)1522-2594(199905)41:5<857::aid-mrm1>3.0.co;2-e
Subject(s) - cartilage , glycosaminoglycan , in vivo , magnetic resonance imaging , gadolinium , chemistry , ex vivo , in vitro , nuclear magnetic resonance , biomedical engineering , nuclear medicine , medicine , radiology , biochemistry , anatomy , biology , physics , microbiology and biotechnology , organic chemistry
Despite the compelling need mandated by the prevalence and morbidity of degenerative cartilage diseases, it is extremely difficult to study disease progression and therapeutic efficacy, either in vitro or in vivo (clinically). This is partly because no techniques have been available for nondestructively visualizing the distribution of functionally important macromolecules in living cartilage. Here we describe and validate a technique to image the glycosaminoglycan concentration ([GAG]) of human cartilage nondestructively by magnetic resonance imaging (MRI). The technique is based on the premise that the negatively charged contrast agent gadolinium diethylene triamine pentaacetic acid (Gd(DTPA) 2‐ ) will distribute in cartilage in inverse relation to the negatively charged GAG concentration. Nuclear magnetic resonance spectroscopy studies of cartilage explants demonstrated that there was an approximately linear relationship between T 1 (in the presence of Gd(DTPA) 2‐ ) and [GAG] over a large range of [GAG]. Furthermore, there was a strong agreement between the [GAG] calculated from [Gd(DTPA) 2‐ ] and the actual [GAG] determined from the validated methods of calculations from [Na + ] and the biochemical DMMB assay. Spatial distributions of GAG were easily observed in T 1 ‐weighted and T 1 ‐calculated MRI studies of intact human joints, with good histological correlation. Furthermore, in vivo clinical images of T 1 in the presence of Gd(DTPA) 2‐ (i.e., GAG distribution) correlated well with the validated ex vivo results after total knee replacement surgery, showing that it is feasible to monitor GAG distribution in vivo. This approach gives us the opportunity to image directly the concentration of GAG, a major and critically important macromolecule in human cartilage. Magn Reson Med 41:857–865, 1999. © 1999 Wiley‐Liss, Inc.