title: The paediatric wrist revisited--findings of bony depressions in healthy children on radiographs compared to MRI.
abstract: BACKGROUND
  The presence of erosions is used for diagnosis and monitoring of disease activity in juvenile idiopathic arthritis (JIA). Assessment of carpal bone erosions in children is challenging due to lack of normal references.
  
  
  OBJECTIVE
  To define normal appearances of bony depressions in the wrist on radiographs and MRI.
  
  
  METHODS
  MRI and radiography of the wrist were performed in 88 healthy children, 5-15 years of age. We assessed the number of bony depressions within the carpals/proximal metacarpals on both modalities, separately and combined.
  
  
  RESULTS
  A total of 75 carpal depressions were identified on radiography compared to 715 on MRI. The number of bony depressions identified radiographically showed no statistically significant difference across age-groups. Within the metacarpals, there was no significant difference between bony depressions identified by MRI or radiography, except at the bases of the second metacarpal.
  
  
  CONCLUSIONS
  Bony depressions that resemble erosions are normal findings in the wrist in children. MRI identifies more depressions than radiographs in the carpus. Some bony depressions occur at typical locations and should be accounted for when assessing the wrist in JIA to avoid overstaging.
authors.affiliation: Department of Radiology, University Hospital North Norway, Breivika, 9038, Tromsø, Norway.
authors.forename: Derk M F
authors.initials: DM
authors.lastname: Avenarius
authors.forename: Lil-Sofie
authors.initials: LS
authors.lastname: Ording Müller
authors.forename: Petter
authors.initials: P
authors.lastname: Eldevik
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Owens
authors.forename: Karen
authors.initials: K
authors.lastname: Rosendahl
mesh_terms: D000293:Adolescent; D001168:Arthritis / Q000000981:diagnostic imaging* / Q000209:etiology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D010014:Osteolysis / Q000150:complications* / Q000175:diagnosis*; D011859:Radiography; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014955:Wrist Joint / Q000000981:diagnostic imaging* / Q000473:pathology*; D014962:X-Ray Film