Age-Related Vascularization and Ossification of Joints in Children: An International Pilot Study to Test Multiobserver Ultrasound Reliability: Arthritis Care and Research

D. Windschall, P. Collado, J. Vojinovic, S. Magni-Manzoni, P. Balint, G.A.W. Bruyn, C. Hernandez-Diaz, J.C. Nieto, V. Ravagnani, N. Tzaribachev, A. Iagnocco, M.A. D'Agostino, E. Naredo, the Outcome Measures in Rheumatology Pediatric Ultrasound Subtask Force

Research output: Contribution to journalArticlepeer-review


Objective: To determine the intra- and interobserver reliability of ultrasound (US)-detected age-related joint vascularization and ossification grading in healthy children. Methods: Following standardized image acquisition and machine setting protocols, 10 international US experts examined 4 joints (wrist, second metacarpophalangeal joint, knee, and ankle) in 12 healthy children (divided into 4 age groups: 2–4, 5–8, 9–12, and 13–16 years). Gray-scale was used to detect the ossification grade, and power Doppler ultrasound (PDUS) was used to detect physiologic vascularization. Ossification was graded from 0 (no ossification) to 3 (complete ossification). A positive PDUS signal was defined as any PDUS signal inside the joint. Kappa statistics were applied for intra- and interobserver reliability. Results: According to the specific joint and age, up to 4 solitary PDUS signals (mean 1.5) were detected within each joint area with predominant localization of the physiologic vascularization in specific anatomic positions: fat pad, epiphysis, physis, and short bone cartilage. The kappa values for ossification grading were 0.87 (range 0.85–0.91) and 0.58 for intra- and interobserver reliability, respectively. The bias-adjusted kappa values for intra- and interobserver reliability were 0.71 (range 0.44–1.00) and 0.69, respectively. Conclusion: Detection of normal findings (i.e., grading of physiologic ossification during skeletal maturation and identification of physiologic vessels) can be highly reliable by using clear definitions and a standardized acquisition protocol. These data will permit development of a reliable and standardized US approach for evaluating pediatric joint pathologies. © 2019, American College of Rheumatology
Original languageEnglish
Pages (from-to)498-506
Number of pages9
JournalArthritis Care Res.
Issue number4
Publication statusPublished - 2020


  • adolescent
  • age
  • ankle
  • Article
  • cartilage
  • child
  • controlled study
  • Doppler ultrasonography
  • echography
  • epiphysis
  • female
  • gray scale echography
  • human
  • human experiment
  • interrater reliability
  • intrarater reliability
  • joint
  • knee
  • male
  • metacarpophalangeal joint
  • normal human
  • ossification
  • physis
  • pilot study
  • vascularization
  • wrist
  • angiogenesis
  • bone development
  • diagnostic imaging
  • physiology
  • preschool child
  • procedures
  • reference value
  • reproducibility
  • synovium
  • Adolescent
  • Child
  • Child, Preschool
  • Female
  • Humans
  • Joints
  • Male
  • Neovascularization, Physiologic
  • Osteogenesis
  • Pilot Projects
  • Reference Values
  • Reproducibility of Results
  • Synovial Membrane
  • Ultrasonography, Doppler


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