title: Test-retest reliability of automated whole body and compartmental muscle volume measurements on a wide bore 3T MR system.
abstract: OBJECTIVE
  To measure the test-retest reproducibility of an automated system for quantifying whole body and compartmental muscle volumes using wide bore 3 T MRI.
  
  
  METHODS
  Thirty volunteers stratified by body mass index underwent whole body 3 T MRI, two-point Dixon sequences, on two separate occasions. Water-fat separation was performed, with automated segmentation of whole body, torso, upper and lower leg volumes, and manually segmented lower leg muscle volumes.
  
  
  RESULTS
  Mean automated total body muscle volume was 19·32 L (SD9·1) and 19·28 L (SD9·12) for first and second acquisitions (Intraclass correlation coefficient (ICC) = 1·0, 95% level of agreement -0·32-0·2 L). ICC for all automated test-retest muscle volumes were almost perfect (0·99-1·0) with 95% levels of agreement 1.8-6.6% of mean volume. Automated muscle volume measurements correlate closely with manual quantification (right lower leg: manual 1·68 L (2SD0·6) compared to automated 1·64 L (2SD 0·6), left lower leg: manual 1·69 L (2SD 0·64) compared to automated 1·63 L (SD0·61), correlation coefficients for automated and manual segmentation were 0·94-0·96).
  
  
  CONCLUSIONS
  Fully automated whole body and compartmental muscle volume quantification can be achieved rapidly on a 3 T wide bore system with very low margins of error, excellent test-retest reliability and excellent correlation to manual segmentation in the lower leg.
  
  
  CONCLUSIONS
  Sarcopaenia is an important reversible complication of a number of diseases. Manual quantification of muscle volume is time-consuming and expensive. Muscles can be imaged using in and out of phase MRI. Automated atlas-based segmentation can identify muscle groups. Automated muscle volume segmentation is reproducible and can replace manual measurements.
authors.affiliation: Department of Radiology, Norfolk & Norwich University Hospital, Norwich, UK.
authors.forename: Marianna S
authors.initials: MS
authors.lastname: Thomas
authors.forename: David
authors.initials: D
authors.lastname: Newman
authors.forename: Olof Dahlqvist
authors.initials: OD
authors.lastname: Leinhard
authors.forename: Bahman
authors.initials: B
authors.lastname: Kasmai
authors.forename: Richard
authors.initials: R
authors.lastname: Greenwood
authors.forename: Paul N
authors.initials: PN
authors.lastname: Malcolm
authors.forename: Anette
authors.initials: A
authors.lastname: Karlsson
authors.forename: Johannes
authors.initials: J
authors.lastname: Rosander
authors.forename: Magnus
authors.initials: M
authors.lastname: Borga
authors.forename: Andoni P
authors.initials: AP
authors.lastname: Toms
mesh_terms: D000328:Adult; D001826:Body Fluids / Q000502:physiology*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000033:anatomy & histology*; D009929:Organ Size; D011446:Prospective Studies; D015203:Reproducibility of Results; D051598:Whole Body Imaging / Q000379:methods*