172 Imaging Ultrasound imaging for the rheumatologist VIII. Ultrasound imaging in osteoarthritis G. Meenagh 1 , E. Filippucci 2 , A. Iagnocco 3 , A. Delle Sedie 4 , L. Riente 4 , S. Bombardieri 4 , G. Valesini 3 , W. Grassi 2 1 Department of Rheumatology, Weston General Hospital, Weston-super-Mare, Bristol, UK; 2 Cattedra di Reumatologia, Università Politecnica delle Marche, Jesi, Italy; 3 Cattedra di Reumatologia, Sapienza - Università di Roma, Roma, Italy; 4 Unità Operativa di Reumatologia, Università di Pisa, Pisa, Italy. Gary Meenagh, MD; Emilio Filippucci, MD; Annamaria Iagnocco, MD; Andrea Delle Sedie, MD; Lucrezia Riente, MD; Stefano Bombardieri, MD, Professor of Rheumatology; Guido Valesini, MD, Professor of Rheumatology; Walter Grassi, MD, Professor of Rheumatology. Please address correspondence to: Prof. Walter Grassi, Cattedra di Reumatologia, Università Politecnica delle Marche, Ospedale “A. Murri”,Via dei Colli 52, 60035 Jesi (AN), Italy. E-mail: walter.grassi@univpm.it Received on March 5, 2007; accepted on March 8, 2007. Clin Exp Rheumatol 2007; 25: 172-175. © Copyright CLINICAL AND EXPERIMENTAL RHEUMATOLOGY 2007. Key words: Ultrasonography, osteoarthritis, synovitis, osteophyte, articular cartilage. ABSTRACT The present review provides an update of the available data and discusses research issues relating to ultrasound (US) imaging in osteoarthritis (OA). Currently, the principal indications for using US in OA include: delineation of changes within articular cartilage (AC) and demonstration of synovial and ad- jacent soft tissue pathology together with injection into OA joints under US guidance. US has been proposed as a possible imaging tool for following the progression of OA. The main priorities requiring the atten- tion of researchers include: addressing difficulties surrounding consensus on definitions of pathology in OA, chart- ing the natural history of AC change in site specific OA, investigation of the link between inflammation and OA and the use of three-dimensional (3D) US in OA. Introduction Musculoskeletal ultrasound (US) has rapidly come to the fore in recent years as one of the most important tools of investigation for rheumatologists (1-5). Throughout Europe and beyond, rheu- matologists are increasingly perform- ing US themselves. Both the research available and training required has pre- dominantly concentrated on the explo- ration of inflammatory disease. There has, however, been increasing interest in the use of US to image and investi- gate structural change in osteoarthritis (OA) (6-8). Plain radiography has been the stand- ard imaging technique for many years to both diagnose and quantify OA. This has inherent limitations including the indirect visualisation of the articular cartilage (AC) and inability to image co-existent soft tissue pathology. US can reliably quantify changes both in AC and soft tissues and would appear to be a neglected imaging modality in OA to date. Research in the area has centred upon knee OA in particular and has attempt- ed to address the following: compari- son between US and plain radiography, correlation of US changes in AC with histomorphometry and the causes of pain in knee OA (9, 10). This review aims to highlight the cur- rent use of US in OA and discuss the available literature surrounding the topic. Clinical applications The principal indications for using US in OA include: delineating progressive changes in AC, demonstrating synovial changes within joints and the visualisa- tion of adjacent soft tissue pathology (6, 11). In addition, US can identify bony changes including osteophytosis and in rare clinical circumstances bone erosion as seen in erosive OA (6, 12, 13). Grey scale US using high quality, high frequency linear transducers are re- quired for imaging the finest details within AC. Classically the normal ana- tomical details of AC are seen best at lower levels of power and gain (6). Power Doppler has limited use in OA to demonstrate hypervascularity of the synovial linings of joints and the inves- tigation of the putative link between inflammation and OA (14, 15). The application of US in OA also ex- tends to the guidance of needles for in- tra-articular injection of various joints and soft tissues (16-20). Sonographic findings The main pathological features detect- ed by US in patients with OA are those related to cartilage damage, joint in- flammation, and osteophyte formation (Table I) (Fig. 1). brought to you by CORE View metadata, citation and similar papers at core.ac.uk provided by Institutional Research Information System University of Turin