title: Alternation of the magnetic resonance signals characteristic of mandibular condyles during growth.
abstract: OBJECTIVE
  In a previous study, we named the magnetic resonance imaging (MRI) signal that is characteristic of mandibular condyles in growing children the "double contour-like structure" (DCLS). In the current study, we evaluated the alternating appearance and disappearance of the DCLS in children as they grow to elucidate the significance of the DCLS.
  
  
  METHODS
  In 11 subjects who were 9-14 years old at the time of the first examination, MRI characteristics of mandibular condyles were sought from fast spin-echo intermediate-weighted images; 2 or 3 years later, repeat MRI were obtained from the same subjects.
  
  
  RESULTS
  At the second examination, 10 of the 16 DCLSs detected at the first examination had disappeared. A significant relationship was found between the alternation of the DCLS and the bone marrow conversion from red to yellow in mandibular condyles. Alternation of the DCLS tended to coincide with eruption of the permanent maxillary second molars. The DCLS was also shown to appear as a hypersignal on T2-weighted images.
  
  
  CONCLUSIONS
  Double contour-like structure signals in mandibular condyles appeared and disappeared as children grew, and these signal alternations may be useful as a criterion for the staging of mandibular condyle development in children. Possible constituents of the DCLS may be hypervascular loose fibrous tissue and a proliferation of cartilage.
authors.affiliation: Department of Dental Radiology, Kyushu Dental College, Kitakyushu, Japan. rad-mori@kyu-dent.ac.jp
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Morimoto
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Tominaga
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Konoo
authors.forename: Tatsurou
authors.initials: T
authors.lastname: Tanaka
authors.forename: Kazunori
authors.initials: K
authors.lastname: Yamaguchi
authors.forename: Jin-ichi
authors.initials: J
authors.lastname: Fukuda
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ohba
mesh_terms: D000293:Adolescent; D001853:Bone Marrow / Q000033:anatomy & histology; D002648:Child; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008335:Mandibular Condyle / Q000254:growth & development*; D008445:Maxillofacial Development; D015588:Observer Variation; D011446:Prospective Studies; D014078:Tooth Eruption