Development and application of new imaging techniques for osteoarthritis

Abstract

In this thesis ‘Development and application of new imaging techniques for osteoarthritis’ new imaging techniques for the assessment of experimental osteoarthritis (OA) in small animal models are described. A novel method for in vivo imaging of cartilage quantity and quality, named micro-CT arthrography, was developed and validated. We showed that the diffusion of a negatively charged contrast medium into the cartilage could determine the relative amount of glycosaminoglycans in the cartilage. By using micro-CT arthrography we could determine very early changes in a small animal model for OA. Furthermore, by using bisphosphonate-enhanced multipinhole- SPECT/CT, we showed the possibility to assess bone turnover in a rat model for OA with high sensitivity. To assess macrophage involvement in OA, folate targeted multi-pinhole-SPECT/CT was used. Folic acid targets the folate receptor, which is expressed abundantly by activated macrophages. By using this technique we showed that there is actual macrophage involvement in experimental OA and that different animal models for OA express different macrophage activity patterns. Addition of these imaging techniques to the imaging portfolio of experimental OA may replace a great deal of the conventional biochemical and histological destructive techniques. The imaging techniques require fewer animals to study and provide accurate quantification. Translation of these new techniques into the clinical setting seems feasible and might allow monitoring of treatment regimes and early recognition of OA.