Ultrasound for Diagnosis and for Guidance and Follow-up of Juvenile Idiopathic
Arthritis
Court-Payen M1, Laurell L2
1
Department of Musculoskeletal Imaging, Gildhøj Private Hospital, Brøndby/Copenhagen,
Denmark. 2Department of Pediatrics, Children's Hospital, Skåne University Hospital, Lund,
Sweden.
Early therapeutic intervention and use of new highly efficacious treatments have improved the
outcome in patients with juvenile idiopathic arthritis (JIA) but have also led to the need for
more precise methods to evaluate disease activity. In adult rheumatology, numerous studies
have established the importance of magnetic resonance imaging (MRI) and ultrasonography
(US), and MRI is considered the reference standard. Nevertheless, due to differences in
disease characteristics and the unique features of the growing skeleton, the findings obtained
in adults are not directly applicable to children. For pediatric patients, US offers specific
advantages over MRI; it is non-invasive, does not require sedation or general anesthesia, is
quickly accessible bedside, and easy to combine with clinical assessment. Agitation of the
patient is rarely a problem, young children can be seated on a parent’s lap or play while being
examined, and multiple locations can be assessed during a single session. Furthermore,
modern high-frequency US transducers used by experienced examiners can provide
unsurpassed resolution of the superficial musculoskeletal structures in children. US is the best
available technique for imaging guidance of steroid injections.
Unfortunately, there are still no validated MRI or US scoring systems for inflammatory and
joint damage abnormalities in JIA, and few studies have been conducted. Ultrasonographic
assessment of disease activity has, however, been proven to be more informative than clinical
examination and is also readily available at point of care. In contrast to MRI, US does not
require sedation of young children, an age group with a high prevalence of JIA.
The diagnostic usefulness of US in areas difficult to assess clinically, such as the ankle and
the wrist regions, will be discussed. In these areas, it is often unclear which anatomical
structures that are inflamed and whether symptoms are due to synovitis, tenosynovitis or both.
US-guidance yields accurate placement of the needle tip and subsequent steroid injection.
Intra-articular steroid injection is a treatment option in JIA for patients with mono- or
oligoarticular JIA but may also be used when a few joints remain actively inflamed during
treatment with systemic disease-modifying drugs. Ankle injections, for example, are
traditionally performed using palpable anatomic landmarks and have been shown to be poorer
than injections at other sites.
It appears that determination of true remission cannot rely solely on clinical examination, but
requires repetitive imaging to confirm the absence of subclinical inflammation. Like in adult
rheumatology, repetitive follow-up examinations with US and color Doppler examination is
attractive because it is non-invasive and lacks ionizing radiation.