Computed tomography detects changes in contrast agent diffusion after collagen cross-linking typical to natural aging of articular cartilage.

Summary Objective The effect of threose-induced collagen cross-linking on the mechanical and diffusive properties of cartilage was investigated in vitro . In particular, we investigated the potential of Contrast Enhanced Computed Tomography (CECT) to detect changes in articular cartilage after increased collagen cross-linking, which is an age-related phenomenon. Methods Osteochondral plugs ( O =6.0mm, n =28) were prepared from intact bovine patellae ( n =7). Two of the four adjacent samples, prepared from each patella, were treated with threose to increase the collagen cross-linking, while the other two specimen served as paired controls. One sample pair was mechanically tested and then mechanically injured using a material testing device. Contrast agent [ioxaglate (Hexabrix™)] diffusion was imaged in the other specimen pair for 25h using CECT. Water fraction, collagen and proteoglycan content, collagen network architecture and the amount of cross-links [hydroxylysyl pyridinoline (HP), lysyl pyridinoline (LP) and pentosidine (Pent)] of the samples were also determined. Results Cartilage collagen cross-linking, both Pent and LP, were significantly ( P P P P Conclusions To conclude, the CECT technique was found to be sensitive at detecting changes in cartilage tissue due to increased collagen cross-linking. This is important since increased cross-linking has been proposed to be related to the increased injury susceptibility of tissue.