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Fat pad tissue, physiological vascularity added to OMERACT ultrasound healthy joint features
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Fat pad tissue and physiological vascularity have been added to the identified and tested definitions of joint components that can be visualized in ultrasonography in healthy children at various age groups, according to research published in Pediatric Rheumatology.
“The Outcome Measures in Rheumatology (OMERACT) [Ultrasonography] Pediatric Task Force was formed to standardize the use of ultrasonography in juvenile arthritis,” Paz Collado, MD, of Severo Ochoa University Hospital, Madrid, and colleagues wrote. “It has developed preliminary B-mode ultrasonography definitions for joint components in healthy children, as well as a standardized ultrasonography scanning procedure specifically adapted to children. However, vascularity of the unossified epiphyseal and physeal cartilage has not been described in detail yet.”
According to Collado and colleagues, aside from unossified cartilage, fat pads, particularly in the knee and ankle joints, can help detect physiological vascularity.
“To describe the vascularity in healthy joints and develop its definition to add to the preliminary B-mode ultrasonography definitions of joint components, would therefore improve the performance of [ultrasound] as an outcome measure in [juvenile idiopathic arthritis] clinical trials,” they wrote.
To determine doppler findings and definitions of normal joint features that be can visualized in children, researchers organized a face-to-face meeting of 10 ultrasonography experts in Germany, some of whom were involved in the creation of the original OMERACT methodology. The group reviewed 40 images representing knees, ankles, wrists and metacarpophalangeal joints of children from previous studies, and developed new definitions for joint components. Those experts then tested those definitions, along with preliminary B-mode- ultrasonography definitions, in 12 healthy children at various age groups.
In the final stage, a panel of 16 international experts were invited to join a web-based process to establish a consensus on the proposed definitions, using the Delphi methodology. A Likert scale of 1 to 5 was used to assess agreement.
The panel ultimately identified physiological vascularity and fat pad tissue as two additional joint components in healthy children. In addition, the experts drafted a series of seven statements to define and validate the two new components:
- Physiological vascularity can be identified via power doppler signal in joint structures at any age during growth;
- Physiological intra-articular vascularity can be identified in children within both the fat pads and unossified joint structures;
- Identification of physiological vascularity and its intra-articular anatomical position is both joint- and age-dependent, particularly among young children;
- Physis can be identified in children as an anechoic unossified structure, intra- or extra-articular according to its anatomical location;
- Fat pad can be identified as an intra-articular structure with heterogeneous echotexture, which may show vascularity;
- Among children in disparate age groups, due to the skeletal development, ossification centers can be identified with different maturation state; and
- Ossification grade is both age- and joint-dependent.
In an online survey, the consensus for the final definitions reached 92.2% agreement for fat pad issue and 100% for physiological vascularity.
“Although these definitions should be considered when [ultrasonography] is applied on children with arthritis in daily practice, further studies are required to evaluate the applicability of these new power doppler definitions to other joints and to explore their potential use in clinical trials,” Collado and colleagues wrote. “The inclusion of these two additional joints components which are linked to detection of doppler signal in pediatric healthy joints will improve the identification of joint abnormalities in pediatric rheumatic diseases.” – by Jason Laday
Disclosure: Collado reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.
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