title: Comparison of MR images for age determination; T1 weighted images (T1WI) versus T2* weighted images (T2*WI).
abstract: OBJECTIVE
  T1WI (T1 weighted image) was acquired in order to grade bone fusion following the studies by FIFA (Federation Internationale de Football Associations). Research using images other than T1WI has not been reported. The aim of this study is to evaluate the grade of epiphyseal fusion by T2* weighted images (T2*WI) and to investigate new findings on T2*WI as compared with T1WI.
  
  
  METHODS
  A total of 87 subjects, all junior football players between the ages of 12 and 17 years old, were examined. T1 and T2* WI were obtained using a 1.2T Open type MR system. The T1WI and T2*WI were rated twice randomly by four radiologists using the FIFA grading system.
  
  
  RESULTS
  The intra-rater reliability for grading was higher in T1WI (The Intraclass Correlation Coefficient (ICC)=0.949-0.985) than in T2*WI (ICC=0.917-0.943). The inter-rater reliability for grading was also higher in T1WI (ICC=0.923) than in T2*WI (ICC=0.867).
  
  
  CONCLUSIONS
  This research showed that T1WI is a better sequence than T2*WI to evaluate bone fusion following FIFA protocol. It was speculated that the reason for this is that T1WI has higher tissue contrast resolution and enables clearer images of the epiphyseal fusion than T2*WI and the grading system by T1WI was not suitable for T2*WI.
authors.affiliation: JFA Medical Center, Fukushima, Japan.
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Shimada
authors.forename: Daisuke
authors.initials: D
authors.lastname: Shimao
authors.forename: Jiro
authors.initials: J
authors.lastname: Kobayashi
authors.forename: Chikako
authors.initials: C
authors.lastname: Nakahori
authors.forename: Mariko
authors.initials: M
authors.lastname: Shimada
authors.forename: Hiroo
authors.initials: H
authors.lastname: Fujimoto
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Misawa
authors.forename: Haruyasu
authors.initials: H
authors.lastname: Kato
authors.forename: Michiko
authors.initials: M
authors.lastname: Dohi