A role for US screening in juvenile idiopathic arthritis.

More than 50 years ago, the introduction of corticosteroid treatment dramatically changed signs and symptoms of a crippling disease now called rheumatoid arthritis. The effects of corticosteroid treatment on synovium have been shown to be measurable, but initial interest in the subject of arthritis documentation seemed lukewarm at best [1]. In recent changes of management of inflammatory arthritis, physicians have modulated their role in therapy of rheumatoid (RA) and juvenile idiopathic arthritis (JIA) from an indiscriminate suppression of inflammation to a targeted immune treatment including tumor necrosis factor inhibition and B-cell depletion [2]. In this setting of immune system therapy, which can lead to life-threatening infections, appropriate imaging proof of inflammatory arthritis becomes paramount. Correct and well-timed diagnosis will help us avoid treating patients who do not have the disease and, on the other hand, let the ones with the disease be treated early enough so that normal tissues are preserved [3]. Treatment can now for the first time stop the devastation that starts with destruction of bone and cartilage in chronic arthritis. Imaging follow-up of the effects of treatment also increases in importance when disease-modifying agents are considered, because the pictorial review can often prove whether a treatment is working. Up until a decade ago, RA and JIA left imprints on radiographs only by erosion and demineralization of bone—late but characteristic findings of joint inflammation. By having to rely on radiology, rheumatologists always seemed one step behind in the battle against the aggression caused by arthritis. The pathologic diagnosis is based on biopsy findings of pannus, a tissue that deforms joints before it attacks the bone. As a diagnostic tool, invasive synovial biopsy is rarely used. Newer methods of imaging have demonstrated pannus and are able to show the healing and reconstruction of erosions under influence of immune regulating agents. Both MRI and sonography have contributed in documentation of disease status and in recording of follow-up therapy. In the paper by Karmazyn et al. [4], the authors show a practical way of evaluating the pannus of JIA. The authors show that one can screen hands of patients using ultrasound, a noninvasive technique that does not use ionizing radiation, does not require sedation and can be repeated cost-effectively. JIA has proved to be a disease difficult to diagnose, likely an amalgam of chronic arthritides with vastly different prognoses [5]. With continued research in the application of ultrasound in JIA, different and potentially more effective treatment regimens will be devised and tested by regular sonographic measurements of synovial thickness. As imagers, we have an opportunity to expand our role in the diagnosis of juvenile idiopathic arthritis from the making of an accurate but delayed diagnosis with radiographs to early diagnosis of pannus and the monitoring of disease activity through sonography or MRI [6]. With a renewed interest in imaging by non-imagers we can also watch more passively and see it all unfold as onlookers at the sidelines. Pediatr Radiol (2007) 37:623–624 DOI 10.1007/s00247-007-0523-0