A Non-Invasive Method for Identifying Fibrocartilage and Articular Cartilage in Radiographs

Abstract

PURPOSE: Detecting early stages of pathology in tendons, ligaments and articular cartilage is problematic. Currently, a histopathological evaluation of biopsied material or arthroscopy is essential for understanding the precise nature of the problem – but both approaches are invasive. Furthermore, biopsies present ethical problems and histological sectioning can be time-consuming. X-rays have conventionally been used to study bone and are regarded as being of very limited use in studying soft tissues. The purpose of this study is to present a non-invasive, radiological image analysis for visualising the structure of articular cartilage and fibrocartilage. METHODS: Samples of the attachment of the Achilles tendon to the calcaneus and articular cartilage from the lateral femoral condyle were removed from dissecting room cadavers. Radiographs of all specimens were taken on a Faxitron MX20 and then processed for routine histology. Analyses were performed on the Faxitron digital images using FIR niters and contour mapping based on parametric and non parametric statistical algorithms. RESULTS: There was a close correspondence between the structural and fractal analyses performed I on digital radiographs and the histological appearance' of the same specimen. This was evident from comparing the images obtained from each radiographic analyses with the corresponding histology images shown below them, for both articular cartilage (Figs 1 and 2 – from normal and osteoarthritic joints respectively) and tendon fibrocartilage (Fig 3). The estimates of tissue thickness obtained by the two methods differed by less than 4.7%.FigureFigureFigureCONCLUSION: Considerable structural detail can be seen in fibrocartilage and articular cartilage in conventional radiographs using algorithmic analyses that should have important clinical applications in detecting early stages of joint and tendon/ ligament degeneration.