title: Contrast-enhanced MRI of the temporomandibular joint: findings in children without juvenile idiopathic arthritis.
abstract: BACKGROUND
  Contrast-enhanced magnetic resonance imaging (MRI) is highly sensitive for assessing temporomandibular joint (TMJ) involvement in juvenile idiopathic arthritis (JIA), but only sparse data exist on normal TMJ appearance in children.
  
  
  OBJECTIVE
  To determine normal MRI appearance and enhancement pattern of pediatric TMJ as basis for diagnosing early arthritis.
  
  
  METHODS
  In 27 children (age range, 1.2-16.8 years) without TMJ pathology undergoing head MRI, fat-saturated T2-weighted (T2W) and postcontrast fat-saturated T1-weighted (T1W) images sagittally aligned to the 54 TMJs, besides standard T1W and T2W images, were assessed for bony and soft tissue signal intensity (SI), the amount of perceptible joint fluid, and contrast enhancement (CE).
  
  
  RESULTS
  Bone marrow SI and CE of the mandible were consistent with varying degrees of residual red marrow in 96% of joints. The mandibular condyles were mostly isointense to the ramus, but in 9% showed mild edema-like bone marrow SI and CE. Small amounts of intraarticular fluid were detected in 31% on T2W images without fat saturation and in 83% on T2W images with fat saturation as fine lines in the upper or lower joint compartment or as small dots in an articular recess. Seventy-nine percent of all TMJs showed intense joint enhancement on early images restricted to areas of intraarticular fluid.
  
  
  CONCLUSIONS
  Small amounts of joint fluid with intense CE are a common MRI finding in TMJs of children without JIA and therefore should not be considered diagnostic for early arthritis.
authors.affiliation: Department of Diagnostic Imaging, University Children's Hospital Zürich, Switzerland.
authors.forename: Raimund
authors.initials: R
authors.lastname: Kottke
authors.affiliation: Division of Rheumatology, University Children's Hospital Zürich, Switzerland.
authors.forename: Rotraud K
authors.initials: RK
authors.lastname: Saurenmann
authors.affiliation: Division of Rheumatology, University Children's Hospital Zürich, Switzerland.
authors.forename: Michel M
authors.initials: MM
authors.lastname: Schneider
authors.affiliation: Clinic for Orthodontics and Pediatric Dentistry, University of Zürich, Switzerland.
authors.forename: Lukas
authors.initials: L
authors.lastname: Müller
authors.affiliation: Department of Pediatric Oncology, University Children's Hospital Zürich, Switzerland.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Grotzer
authors.affiliation: Department of Diagnostic Imaging, University Children's Hospital Zürich, Switzerland christian.kellenberger@kispi.uzh.ch.
authors.forename: Christian J
authors.initials: CJ
authors.lastname: Kellenberger
mesh_terms: D000293:Adolescent; D001171:Arthritis, Juvenile / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media; D005260:Female; D005682:Gadolinium; D019786:Gadolinium DTPA; D006571:Heterocyclic Compounds; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007223:Infant; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009942:Organometallic Compounds; D013704:Temporomandibular Joint / Q000033:anatomy & histology* / Q000473:pathology
chemical_list: D003287:Contrast Media; D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; C062402:gadoteridol; D005682:Gadolinium; D019786:Gadolinium DTPA
keywords: Pediatrics; inflammation; jaw; joints; magnetic resonance imaging (MRI); normal variants