title: T1 rho MR imaging characteristics of human anterior tibial and gastrocnemius muscles.
abstract: OBJECTIVE
  The authors evaluated the value of T1 rho in relation to T1 and T2 in the characterization of human muscles.
  
  
  METHODS
  The authors studied the effect of muscle type (anterior tibial [AT] and gastrocnemius [GC]), sex, and age on 1/T1 and 1/T2 at 0.1 T and on 1/ T1 rho at locking-field B1s (spin-locking radio-frequency magnetic induction field) of 10-160 microT in 38 healthy volunteers. The contrast-to-noise ratio (CNR) between muscle and fat was evaluated with different T1-, T2-, and T1 rho-weighted magnetic resonance (MR) sequences.
  
  
  RESULTS
  The 1/T1, 1/T2, and 1/T1 rho were slightly higher in AT than in GC muscles. The 1/T2 and 1/T1 rho of AT muscles showed a sex dependence, whereas no correlation with age was found. The CNR of the T1 rho-weighted images did not markedly differ from that of the T1- and T2-weighted images.
  
  
  CONCLUSIONS
  T1 rho is as sensitive as T2 to the composition of muscle, whereas T1 is less sensitive. In MR imaging of normal muscle, T1 rho and T2 provide a relatively similar tissue contrast.
authors.affiliation: Department of Diagnostic Radiology, University of Turku, Finland.
authors.forename: A
authors.initials: A
authors.lastname: Virta
authors.forename: M
authors.initials: M
authors.lastname: Komu
authors.forename: N
authors.initials: N
authors.lastname: Lundbom
authors.forename: M
authors.initials: M
authors.lastname: Kormano
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology; D000328:Adult; D000367:Age Factors; D000368:Aged; D000704:Analysis of Variance; D016477:Artifacts; D001823:Body Composition; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted; D007866:Leg / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000033:anatomy & histology*; D012737:Sex Factors