Differences in MRI findings between subgroups of recent-onset childhood arthritis.
BACKGROUND
MRI is sensitive for joint inflammation, but its ability to separate subgroups of arthritis in children has been questioned. Infectious arthritis (IA), postinfectious arthritis (PA), transient arthritis (TA) and juvenile idiopathic arthritis (JIA) are subgroups that may need early, different treatment.


OBJECTIVE
To determine whether MRI findings differ in IA, PA/TA and JIA in recent-onset childhood arthritis.


METHODS
Fifty-nine children from a prospective study of incidence of arthritis (n = 216) were, based on clinical and biochemical criteria, examined by MRI. Joint fluid, synovium, bone marrow, soft tissue and cartilage were scored retrospectively and analysed by Pearson chi-square test and logistic regression analysis.


RESULTS
Fifty-nine children had MRI of one station. IA was suggested by bone marrow oedema (OR 7.46, P = 0.011) and absence of T1-weighted and T2-weighted low signal intensity synovial tissue (OR 0.06, P = 0.015). Furthermore, soft-tissue oedema and reduced contrast enhancement in the epiphyses were more frequent in children with IA. JIA correlated positively with low signal intensity synovial tissue (OR 13.30, P < 0.001) and negatively with soft-tissue oedema (OR 0.20, P = 0.018). No significant positive determinants were found for PA/TA, but bone marrow oedema, soft-tissue oedema, irregular thickened synovium and low signal intensity synovial tissue was less frequent than in IA/JIA.


CONCLUSIONS
In children with high clinical suspicion of recent onset arthritis, there was a significant difference in the distribution of specific MRI features among the diagnostic groups.
Department of Radiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway. eva.kirkhus@oslo-universitetssykehus.no
Eva
E
Kirkhus
Berit
B
Flatø
Oystein
O
Riise
Tor
T
Reiseter
Hans-Jørgen
HJ
Smith
D000293:Adolescent; D000704:Analysis of Variance; D001168:Arthritis / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D016015:Logistic Models; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009664:Norway / Q000453:epidemiology; D011446:Prospective Studies; D012189:Retrospective Studies
D003287:Contrast Media