title: Analyzer-based imaging technique in tomography of cartilage and metal implants: a study at the ESRF.
abstract: Monitoring the progression of osteoarthritis (OA) and the effects of therapy during clinical trials is still a challenge for present clinical imaging techniques since they present intrinsic limitations and can be sensitive only in case of advanced OA stages. In very severe cases, partial or complete joint replacement surgery is the only solution for reducing pain and restoring the joint functions. Poor imaging quality in practically all medical imaging technologies with respect to joint surfaces and to metal implant imaging calls for the development of new techniques that are sensitive to stages preceding the point of irreversible damage of the cartilage tissue. In this scenario, X-ray phase contrast modalities could play an important role since they can provide improved contrast compared to conventional absorption radiography, with a similar or even reduced tissue radiation dose. In this study, the analyzer-based imaging (ABI), a technique sensitive to the X-ray refraction and permitting a high scatter rejection, has been successfully applied in vitro on excised human synovial joints and sheep implants. Pathological and healthy joints as well as metal implants have been imaged in projection and computed tomography ABI mode at high resolution and clinically compatible doses (<10 mGy). Volume rendering and segmentation permitted visualization of the cartilage from volumetric CT-scans. The results demonstrate that ABI can provide an unequivocal non-invasive diagnosis of the state of disease of the joint and be considered a new tool in orthopaedic research.
authors.affiliation: European Synchrotron Radiation Facility (ESRF), 6 rue Jules Horowitz, BP220, 38043 Grenoble, France. coan@esrf.fr
authors.forename: Paola
authors.initials: P
authors.lastname: Coan
authors.forename: Juergen
authors.initials: J
authors.lastname: Mollenhauer
authors.forename: Andreas
authors.initials: A
authors.lastname: Wagner
authors.forename: Carol
authors.initials: C
authors.lastname: Muehleman
authors.forename: Alberto
authors.initials: A
authors.lastname: Bravin
mesh_terms: D000465:Algorithms; D000843:Ankle Joint / Q000000981:diagnostic imaging*; D002358:Cartilage, Articular / Q000000981:diagnostic imaging*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008670:Metals; D010003:Osteoarthritis / Q000000981:diagnostic imaging*; D019736:Prostheses and Implants; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods; D012031:Refractometry / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014056:Tomography, X-Ray / Q000379:methods*
chemical_list: D008670:Metals