Amendment of the OMERACT ultrasound definitions of joints' features in healthy children when using the DOPPLER technique

Abstract

Background: Recently preliminary ultrasonography (US) definitions, in B mode, for normal components of pediatric joints have been developed by the OMERACT US group. The aim of the current study was to include Doppler findings in the evaluation and definition of normal joint features that can be visualized in healthy children at different age groups.

Methods: A multistep approach was used. Firstly, new additional definitions of joint components were proposed during an expert meeting. In the second step, these definitions, along with the preliminary B-mode-US definitions, were tested for feasibility in an exercise in healthy children at different age groups. In the last step, a larger panel of US experts were invited to join a web-based consensus process in order to approve the developed definitions using the Delphi methodology. A Likert scale of 1-5 was used to assess agreement.

Results: Physiological vascularity and fat pad tissue were identified and tested as two additional joint components in healthy children. Since physiological vascularity changes over the time in the growing skeleton, the final definition of Doppler findings comprised separate statements instead of a single full definition. A total of seven statements was developed and included in a written Delphi questionnaire to define and validate the new components. The final definitions for fat pad and physiological vascularity agreed by the group of experts reached 92.9% and 100% agreement respectively in a web survey.

Conclusion: 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 abnormalities in children with joint pathologies.

Keywords: Joint anatomy; Pediatric rheumatology; Power-Doppler; Ultrasonography.

Fig. 1

US images show normal anatomy of the knee joint. The upper images (a, b). We see the distal epiphyseal end of the femur with its secondary ossification centre (asterisk). Note a physiological vessel (arrow) in the epiphyseal cartilage of the femoral condyle (a) and in the quadriceps fat pad (b). Every vessel should be proved in longitudinal (c) and transverse view (d)

Fig. 2

Longitudinal dorsal view of a healthy ankle joint. The US image shows the location of intracapsular but extrasynovial fatty tissue, the presence of physis and epiphyseal cartilage in distal end of the tibia (*). 2nd oc: secondary ossification centre of the tibia

Fig. 3

Midsagittal plane of the knee joint a 5-year-old healthy boy. The image shows physiologic joint vascularity (arrow head) located in the quadriceps fat pad (arrow)

Fig. 4

Longitudinal view of the dorsal aspect of the wrist joint in a 6-year-old child. The upper images (a, b) show the normal sonoanatomy on Grey-scale US (a) and power-Doppler US (b) showing single vessels close to os capitate. The lower images (c, d, e) show synovitis of the wrist joint in a patient with JIA. Synovial vascularity detected in the joint recesses by Doppler (image d, power Doppler and image e, color Doppler) reflects active inflammation. The distal epiphyseal cartilage of radius (er) is visible as an anechoic structure surrounding the secondary ossification nucleus (*). Dynamic examination let distinguish the epiphyseal cartilage of radius from effusion/synovitis (syn)