title: Early detection of temporomandibular joint arthritis in children with juvenile idiopathic arthritis - the role of contrast-enhanced MRI.
abstract: BACKGROUND
  Early treatment of temporomandibular joint (TMJ) arthritis is crucial in children with juvenile idiopathic arthritis (JIA) to prevent permanent functional impairment. As involvement of TMJs is often asymptomatic, contrast-enhanced MRI is regarded as the most sensitive noninvasive diagnostic tool.
  
  
  OBJECTIVE
  To evaluate the degree of contrast enhancement in TMJs of children and adolescents with JIA in comparison to normal controls from a previous study.
  
  
  METHODS
  Dynamic contrast-enhanced MRI of 50 children and adolescents with JIA (6.3 to 18 years of age; mean: 12 years) were retrospectively analysed. We assessed morphological abnormalities and postcontrast time-intensity curves of the soft joint tissue and the mandibular condyle. Ratios were calculated to quantify postcontrast signal intensities (SI) in relation to precontrast SI at initial (1 min postcontrast) and maximum (6 min postcontrast) increase.
  
  
  RESULTS
  Time-intensity curves followed similar biphasic patterns in normal and pathological joints. In joints with morphological signs of arthritis, mean SI ratios were on average higher than in normal joints of the reference group, but ranges of values widely overlapped. Arthritis: mean initial increase of SI 62% (±2 S.D. 18-105%), mean maximum SI 106% higher than precontrast (±2 S.D. 46-166%). Normal: mean initial increase of SI 49% (±2 S.D. 14- 85%), mean maximum of SI 73% (±2 S.D. 23-123%).
  
  
  CONCLUSIONS
  Given this considerable overlap of results in dynamic contrast-enhanced MRI, the degree of contrast enhancement alone did not allow differentiation between TMJs with and without signs of inflammation. Thickening of the soft joint tissue seems to remain the earliest sign to reliably indicate TMJ arthritis.
authors.affiliation: Pediatric Radiology, Radiologisches Institut, Olgahospital Klinikum Stuttgart, Kriegsbergstr. 62, D-70174, Stuttgart, Germany, t.vonkalle@klinikum-stuttgart.de.
authors.forename: Thekla
authors.initials: T
authors.lastname: von Kalle
authors.forename: Tina
authors.initials: T
authors.lastname: Stuber
authors.forename: Peter
authors.initials: P
authors.lastname: Winkler
authors.forename: Jan
authors.initials: J
authors.lastname: Maier
authors.forename: Toni
authors.initials: T
authors.lastname: Hospach
mesh_terms: D000293:Adolescent; D001168:Arthritis / Q000175:diagnosis; D001171:Arthritis, Juvenile / Q000150:complications*; D002648:Child; D003287:Contrast Media; D042241:Early Diagnosis; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging; D008297:Male; D012189:Retrospective Studies; D013704:Temporomandibular Joint / Q000473:pathology*; D013705:Temporomandibular Joint Disorders / Q000150:complications* / Q000175:diagnosis*
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA