title: Quantifying Synovial Enhancement of the Pediatric Temporomandibular Joint.
abstract: OBJECTIVE
  The purposes of this study were to assess a novel method for quantifying temporomandibular joint (TMJ) synovial enhancement on gadolinium-enhanced magnetic resonance imaging (MRI) and to establish normative values to allow early detection of synovitis.
  
  
  METHODS
  This is a retrospective cohort study of pediatric patients (aged 0 to 16 years) without jaw pathology who underwent MRI scans with contrast that included the TMJs. From a coronal T1-weighted image, the signal intensity within the superior and inferior joint spaces was divided by the signal intensity of the longus capitis muscle to establish a ratio by age. Intrarater reliability and inter-rater reliability were assessed. A mixed-model regression analysis was used to determine the 95% specificity threshold for normal ratios.
  
  
  RESULTS
  Temporal and optic nerve MRI scans of 158 patients were included. Normative synovial enhancement ratios (95% specificity) thresholds were established: 1.52, 1.68, and 1.55 for superior joint space, inferior joint space, and average of both joint spaces, respectively. Intrarater and inter-rater agreement was excellent.
  
  
  CONCLUSIONS
  A ratio of signal intensity of the TMJ synovium to the longus capitis is a reliable method to quantify enhancement controlling for time after contrast infusion and may be useful for diagnosis of TMJ synovitis.
authors.affiliation: Assistant Professor, Department of Oral and Maxillofacial Surgery, Massachusetts General Hospital, Harvard School of Dental Medicine, Boston, MA. Electronic address: zpeacock@partners.org.
authors.forename: Zachary S
authors.initials: ZS
authors.lastname: Peacock
authors.affiliation: DMD Candidate, Harvard School of Dental Medicine, Boston, MA.
authors.forename: Pouya
authors.initials: P
authors.lastname: Vakilian
authors.affiliation: Director, Pediatric Neuroradiology; Instructor, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA.
authors.forename: Paul
authors.initials: P
authors.lastname: Caruso
authors.affiliation: Instructor, Department of Plastic and Oral Surgery, Boston Children's Hospital, Harvard School of Dental Medicine, Boston, MA.
authors.forename: Cory M
authors.initials: CM
authors.lastname: Resnick
authors.affiliation: Assistant Professor, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA.
authors.forename: Mark
authors.initials: M
authors.lastname: Vangel
authors.affiliation: Walter C. Guralnick Distinguished Professor, Department of Oral and Maxillofacial Surgery, Massachusetts General Hospital, Harvard School of Dental Medicine, Boston, MA.
authors.forename: Leonard B
authors.initials: LB
authors.lastname: Kaban
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009900:Optic Nerve / Q000000981:diagnostic imaging / Q000473:pathology; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013585:Synovitis / Q000000981:diagnostic imaging* / Q000473:pathology*; D013704:Temporomandibular Joint / Q000000981:diagnostic imaging* / Q000473:pathology*
chemical_list: D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA