Fig. 4.

Image atlas for Calcified cartilage and SB changes in human OC tissue as detected by CEμCT (μCT or μCT with histogram stretching for enhanced contrast) or LM of stained tissue sections (safranin O, picrosirius, and H&E). μCT visualized clearly vascular infiltration (VI), tidemark (T), multiple tidemarks and SB sclerosis (SB scl.) (A. and B.). While not very clear, the cartilage-bone interface (CBI) was also visible in μCT (B.). As reported before¹², we also in this study observed a contrast void near the tidemark in the μCT image (B.), corresponding to a slow diffusion area for the contrast agent (potentially due to high proteoglycan content in this region). The information complementary to conventional histology is the clear visualization of vascular infiltration, i.e., contrast agent diffuses from SB into cartilage through blood vessel cavities and into the void highlighting the locations of diffusion (B., VI + arrows pointing downwards).