Bansal S. Arthritis: Animal models of oral tolerance. Ann NY Acad Sci 1996;778:297±305. 20. Neurath MF, Fuss I, Kelsall BL, Prseky DH, Waegell W, Strober W. Experimental granulomatous colitis in mice is abrogated by induction of TFG-b-mediated oral tolerance. J Exp Med 1996;183:2605±16. MUSCULOSKELETAL ULTRASOUND IMAGING: A NEW DIAGNOSTIC TOOL FOR THE RHEUMATOLOGIST? RHEUMATOLOGISTS have long desired an objective technique which would assist in the diagnosis of in- ¯ammatory conditions of the musculoskeletal system, and enable changes in disease progression and activity to be monitored in conditions such as osteoarthritis (OA) and rheumatoid arthritis (RA). Eective examination of the soft tissues and joints has depended largely on the clinical skills of the rheumatologist backed up by imaging techniques such as routine radiography, CT scanning, joint scin- tigraphy, infrared thermography and, more recently, by magnetic resonance imaging (MRI). All of these imaging techniques have their drawbacks in terms of the nature of the information provided and both its sensitivity and speci®city. MRI has proved to be an exciting modality for imaging musculoskeletal soft tissues, and technical advances raise the prospect of clear and reproducible images of cartilage being achievable, thus allowing early joint erosions to be identi®ed and monitored in RA [1]. However, MRI is expensive and, at present, cannot be used at the bed- side or in the clinic. The use of ultrasound as an imaging modality in medicine was pioneered by the Glasgow obstetrician Ian Donald [2], but although it has been applied to the musculoskeletal system since the 1970s [3], more recent developments in real-time sonography and the use of high-resolution transducers have enabled high- quality images of soft tissues to be achieved. Ultrasound images of both super®cial and deep struc- tures can readily be obtained and, with the introduc- tion of Power Doppler sonography, tissue perfusion may also be measured [4]. In the UK, ultrasound imaging of the musculoskeletal system has been widely used in veterinary practice for the diagnosis of soft-tissue injuries in racehorses and has only recently begun to be used by mainly radiologists as an im- aging tool in rheumatology [5]. It is particularly useful in the detection of ¯uid in inaccessible joints such as the hip and, consequently, for the diagnosis of sepsis and loosening in hip joint prostheses [6]. Soft-tissue abnormalities, such as proliferating syno- vium, bursae, joint capsule rupture, tendonitis and tendon rupture, can all be visualized, and joint aspiration and synovial biopsy can be readily per- formed under ultrasound guidance [7]. There are, of course, limitations in the use of mus- culoskeletal ultrasound. In particular, bone cannot be readily imaged because of the sound wave scattering which occurs at the soft tissue/bone interface. The quality and interpretation of the ultrasound images are also greatly dependent on the expertise and experience of the operator [8], and a good working knowledge of joint and soft-tissue anatomy, as well as an understanding of the clinical context of the problem to be investigated, are necessary if a sensible ultrasound report is to be obtained. In this regard, the clinical rheumatologist should have the necessary knowledge and skills to make an ultrasound examina- tion a logical extension of the clinical examination of the musculoskeletal system. It should be possible for rheumatologists to emulate what cardiologists have done with echocardiography, with current techniques of musculoskeletal ultrasound. It is, therefore, im- portant that rheumatologists in training obtain a good working knowledge of the technique and its potential applications in musculoskeletal disease. This need has already been recognized by the European Board of Rheumatology in its training syllabus [8]. Future developments in ultrasound imaging will include imaging a joint during movement, the con- struction of three-dimensional images that are com- puter processed, the use of intra-articular imaging and the employment of contrast materials that are tissue speci®c [9]. These will open up exciting possibi- lities for clinical rheumatologists, leading to more precise diagnostic capabilities and more eective ther- apeutic interventions. As far as rheumatologists are concerned, ultrasound is the sound of the future. P. BALINT and R. D. STURROCK* National Institute of Rheumatology and Physiotherapy, Budapest, Hungary and *Centre for Rheumatic Diseases, University Department of Medicine, Glasgow Royal In®rmary REFERENCES 1. Peterfy CG. MRI in the assessment of synovium and cartilage. Br J Rheumatol 1996;35(suppl. 3):3±5. 2. Donald I. SonarÐthe story of an experiment. Ultrasound Med Biol 1974;1:109±17. 3. Cooperberg PL, Tsang I, Truelove L et al. Gray scale ultrasound in the evaluation of rheumatoid arthritis of the knee. Radiology 1978;126:759±63. 4. Breidah WH, Newman JS, Taljanovic MS. Power Doppler Sonography in the assessment of musculo- skeletal ¯uid collections. Am J Roentgenol 1996;166:1443±6. EDITORIALS 1141 Downloaded from https://academic.oup.com/rheumatology/article/36/11/1141/1782647 by guest on 06 July 2022