title: Measurement of intramuscular fat by muscle echo intensity.
abstract: BACKGROUND
  The aim of this study was to compare ultrasound echo intensity (EI) with high-resolution T1 -weighted MRI and to establish calibration equations to estimate percent intramuscular fat from EI.
  
  
  METHODS
  Thirty-one participants underwent both ultrasound and MRI testing of 4 muscles: rectus femoris (RF); biceps femoris (BF); tibialis anterior (TA); and medial gastrocnemius (MG).
  
  
  RESULTS
  Strong correlations were found between MRI percent fat and muscle EI after correcting for subcutaneous fat thickness (r = 0.91 in RF, r = 0.80 in BF, r = 0.80 in TA, r = 0.76 in MG). Three types of calibration equations were established.
  
  
  CONCLUSIONS
  Muscle ultrasound is a practical and reproducible method that can be used as an imaging technique for examination of percent intramuscular fat. Future ultrasound studies are needed to establish equations for other muscle groups to enhance its use in both research and clinical settings.
authors: Department of Kinesiology, University of Georgia, Athens, Georgia, USA.
authors: Hui-Ju
authors: HJ
authors: Young
authors: Department of Kinesiology, University of Georgia, Athens, Georgia, USA.
authors: Nathan T
authors: NT
authors: Jenkins
authors: Department of Physics and BioImaging Research Center, University of Georgia, Athens, Georgia, USA.
authors: Qun
authors: Q
authors: Zhao
authors: Department of Kinesiology, University of Georgia, Athens, Georgia, USA.
authors: Kevin K
authors: KK
authors: Mccully
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D013223:Statistics as Topic; D050151:Subcutaneous Fat / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D014463:Ultrasonography; D055815:Young Adult
keywords: MRI; intramuscular fat; muscle; muscle EI; muscle composition; ultrasound