Propagation phase-contrast micro-computed tomography allows laboratory-based three-dimensional imaging of articular cartilage down to the cellular level

• Published in: Osteoarthritis and cartilage 2020-01, Vol.28 (1), p.102-111
• Main Authors: Clark, J.N., Garbout, A., Ferreira, S.A., Javaheri, B., Pitsillides, A.A., Rankin, S.M., Jeffers, J.R.T., Hansen, U.
• Format: Article
• Language: English
• Subjects: Animals; Articular cartilage; Cartilage, Articular - cytology; Cartilage, Articular - ultrastructure; Cattle; Chondrocyte; Chondrocytes - ultrastructure; Contrast Media; Imaging; Imaging, Three-Dimensional - methods; Micro-CT; Microscopy, Phase-Contrast - methods; Osteoarthritis; X-Ray Microtomography - methods
• ISSN: 1063-4584; 1522-9653
• DOI: 10.1016/j.joca.2019.10.007

High-resolution non-invasive three-dimensional (3D) imaging of chondrocytes in articular cartilage remains elusive. The aim of this study was to explore whether laboratory micro-computed tomography (micro-CT) permits imaging cells within articular cartilage. Bovine osteochondral plugs were prepared four ways: in phosphate-buffered saline (PBS) or 70% ethanol (EtOH), both with or without phosphotungstic acid (PTA) staining. Specimens were imaged with micro-CT following two protocols: 1) absorption contrast (AC) imaging 2) propagation phase-contrast (PPC) imaging. All samples were scanned in liquid. The contrast to noise ratio (C/N) of cellular features quantified scan quality and were statistically analysed. Cellular features resolved by micro-CT were validated by standard histology. The highest quality images were obtained using propagation phase-contrast imaging and PTA-staining in 70% EtOH. Cellular features were also visualised when stained in PBS and unstained in EtOH. Under all conditions PPC resulted in greater contrast than AC (p