Investigation of apparent diffusion constant as an indicator of early degenerative disease in articular cartilage.
OBJECTIVE
To investigate the apparent diffusion constant (ADC) as a prospective magnetic resonance imaging (MRI) marker of early degeneration in articular cartilage.


METHODS
Early degenerative changes were studied using in vitro MRI on cartilage-bone specimens excised from human femoral condyles. The loss of proteoglycans developed in vivo due to a degenerative process was compared with a gadolinium diethylenetriamine pentaacetate anion (Gd-DTPA(2-)) enhanced decrease of T(1) relaxation times, and with an increase of ADCs and T(2) relaxation times.


RESULTS
Contrast enhanced T(1) values decreased and the diffusion constants increased in cartilage regions with depleted proteoglycans. The relative changes in diffusion constants were smaller than those of Gd-DTPA(2-) enhanced T(1), and in some proteoglycan-depleted regions no changes in the diffusion constants were detected. T(2) relaxation times showed considerable spatial variability that did not correlate with proteoglycan concentration.


CONCLUSIONS
In contrast to Gd-DTPA(2-) enhanced T(1), which reflects changes in chemical composition, diffusion constants may reflect structural degradation of the cartilage matrix.
Mlynárik
Vladimír
V
Department of Radiology, University of Vienna, Vienna, Austria.
Sulzbacher
Irene
I
Bittsanský
Michal
M
Fuiko
Reinhard
R
Trattnig
Siegfried
S
D002358:Cartilage, Articular / Q000378:metabolism* / Q000473:pathology; D003287:Contrast Media; D019786:Gadolinium DTPA; D006801:Humans; D066298:In Vitro Techniques; D007719:Knee Joint; D008279:Magnetic Resonance Imaging / Q000379:methods*; D011509:Proteoglycans / Q000032:analysis
D003287:Contrast Media; D011509:Proteoglycans; D019786:Gadolinium DTPA