title: A simplified method of T(1)ρ mapping in clinical assessment of knee joint.
abstract: OBJECTIVE
  we assessed the clinical utility of our proposed simplified method for T(1)ρ mapping calculations.
  
  
  METHODS
  ten healthy subjects underwent scanning on a 3-tesla magnetic resonance system using an 8-channel phased-array coil. For each subject, we obtained sagittal T(1)ρ-prepared images using 5 different time of spin-lock pulses (TSL=1, 20, 40, 60, and 80 ms), produced conventional T(1)ρ maps (cT(1)ρ maps) using all TSLs, and recomputed our proposed simplified T(1)ρ maps (sT(1)ρ maps) using a decreasing number of TSLs (from 4 to 2). We then investigated the differences and correlations in T(1)ρ values of the tissues obtained using different numbers of spin-lock times.
  
  
  RESULTS
  there was a strong positive correlation (single measure intraclass correlation coefficient=0.948; 95% confidence interval=0.911 to 0.970) in T(1)ρ values of tissues between the cT(1)ρ and sT(1)ρ [1, 80] maps. The 2 maps were comparable, though there was a small difference in T(1)ρ value between the two. The total scan time to acquire the data from 5 spin-lock times was 16 min 15 s. Similarity of the T(1)ρ [1, 80] map with the conventional approach reduced scan time by 60%, to 6 min 30 s.
  
  
  CONCLUSIONS
  the clinical relevance of our proposed simplified method is potentially similar to that of the conventional method, and our method requires a shorter examination time and generally preserves the reliability of the T(1)ρ relaxation time of the tissues.
authors.affiliation: Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka, Japan. ytaka@radiol.med.kyushu-u.ac.jp
authors.forename: Yukihisa
authors.initials: Y
authors.lastname: Takayama
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Hatakenaka
authors.forename: Takashi
authors.initials: T
authors.lastname: Yoshiura
authors.forename: Ken
authors.initials: K
authors.lastname: Okazaki
authors.forename: Kei
authors.initials: K
authors.lastname: Nishikawa
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Okuaki
authors.forename: Ivan
authors.initials: I
authors.lastname: Zimine
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Honda
mesh_terms: D000328:Adult; D002358:Cartilage, Articular / Q000033:anatomy & histology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D007719:Knee Joint / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D012016:Reference Values; D015203:Reproducibility of Results