SELF-DIFFUSION MONITORS DEGRADED CARTILAGE

This article demonstrates that both the bulk water self-diffusion coef ficient (D) and the spatially resolved variation in D for lesion canin e cartilage due to osteoarthritis is increased by about 25% over that of surrounding cartilage. This increase in D can be mimicked by enzyma tic degradation of cartilage with trypsin, hyaluronidase, and collagen ase, or by mechanical means, However, it is established here using exc ised disks of living cartilage whose proteoglycan and collagen content s were manipulated by biochemical intervention in tissue culture that the diffusion measurement is not sensitive to the proteoglycan content of cartilage, Instead, self-diffusion appears to monitor mesoscopic ( nonspecific) tissue damage, These results show that D, measured in a s patially resolved manner by pulsed field gradient nuclear magnetic res onance imaging can localize regions of cartilage degradation. (C) 1995 Acdemic Press, Inc.