title: The paediatric wrist revisited: redefining MR findings in healthy children.
abstract: OBJECTIVE
  During a multicentre study on juvenile idiopathic arthritis, wide variations were observed in bone shape, signal intensity and volume of joint fluid as shown by MRI which in part appeared to be unrelated to disease activity. A study was undertaken to examine these features in a cohort of healthy children.
  
  
  METHODS
  88 children of mean age 9.8 years (range 5-15) underwent MRI imaging (T1-weighted Spin Echo and Spectral Selection Attenuated Inversion Recovery (SPAIR)) of the left wrist. The number of bony depressions, distribution and amount of joint fluid and the presence of bone marrow changes were assessed.
  
  
  RESULTS
  Bony depressions were present in all children, increasing with age from a mean of 4.0 in children aged 4-6 years to 9.2 in those aged 12-15 years (p<0.001)). 45 of 84 children (53.6%) had a high signal on SPAIR with a corresponding low signal on T1 in at least one bone. No associations were seen between bone marrow change (present or not) and sex (p=0.827) or sports club membership (p=0.616). All children had visible joint fluid in at least one of the joints assessed. No associations were seen between the presence of joint fluid and age group, except for the radius/scaphoid and capitate-scaphoid joints and a recess lateral to the hamate.
  
  
  CONCLUSIONS
  It is important to be aware of the high prevalence of bony depressions, signal changes suggestive of bone marrow oedema and the volume of joint fluid seen in normal children. Such findings must be interpreted with care in children with suspected disease such as juvenile arthritis.
authors.affiliation: Department of Radiology, University Hospital North Norway, Tromsø, Norway. lil-sofie.ording.muller@unn.no
authors.forename: Lil-Sofie Ording
authors.initials: LS
authors.lastname: Müller
authors.forename: D
authors.initials: D
authors.lastname: Avenarius
authors.forename: B
authors.initials: B
authors.lastname: Damasio
authors.forename: O P
authors.initials: OP
authors.lastname: Eldevik
authors.forename: C
authors.initials: C
authors.lastname: Malattia
authors.forename: K
authors.initials: K
authors.lastname: Lambot-Juhan
authors.forename: L
authors.initials: L
authors.lastname: Tanturri
authors.forename: C M
authors.initials: CM
authors.lastname: Owens
authors.forename: K
authors.initials: K
authors.lastname: Rosendahl
mesh_terms: D000293:Adolescent; D000375:Aging / Q000473:pathology; D001853:Bone Marrow / Q000033:anatomy & histology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D011446:Prospective Studies; D012016:Reference Values; D013582:Synovial Fluid / Q000166:cytology; D014955:Wrist Joint / Q000033:anatomy & histology*