title: Aging effects on human calf muscle properties assessed by MRI at 3 Tesla.
abstract: OBJECTIVE
  To determine age-related changes in MR properties as T2 and T2* relaxation times, fat content, and magnetization transfer in the human calf, and comparison of these effects in different muscle groups.
  
  
  METHODS
  Studies were performed on 12 "younger" (mean, 31.2 +/- 6.1 years) and 11 "older" healthy adult individuals (mean, 66.1 +/- 7.8 years). The tibialis anterior muscle, the soleus muscle and the gastrocnemius muscle were examined at rest in a 3 Tesla whole-body MR unit. T2 and T2*, muscular fat content and magnetization transfer ratios (MTR) were determined. Results of the two age groups were compared, and differences between the muscle groups were investigated.
  
  
  RESULTS
  Increase of T2 and muscular fat was detected with age with significant difference between the age groups. The extent of fatty infiltration was much more variable for the "older" group. For both age groups, the tibialis anterior muscle showed the lowest fat content with 1.2 +/- 0.4% in the "young" group and 2.3 +/- 0.7% in the "older" group. A strong correlation between fat content and T2 was found, while the groups did not significantly differ regarding T2*. Decrease in the MTR could only be shown for the tibialis anterior muscle with age.
  
  
  CONCLUSIONS
  Age-related changes in healthy human calf musculature were found. Further studies might show possible correlations of age-dependent changes with physical efficiency and susceptibility to diseases like type 2 diabetes.
authors.affiliation: Department of Diagnostic and Interventional Radiology, Eberhard-Karls University, Tübingen, Germany. nina.schwenzer@med.uni-tuebingen.de
authors.forename: Nina F
authors.initials: NF
authors.lastname: Schwenzer
authors.forename: Petros
authors.initials: P
authors.lastname: Martirosian
authors.forename: Jürgen
authors.initials: J
authors.lastname: Machann
authors.forename: Christina
authors.initials: C
authors.lastname: Schraml
authors.forename: Günter
authors.initials: G
authors.lastname: Steidle
authors.forename: Claus D
authors.initials: CD
authors.lastname: Claussen
authors.forename: Fritz
authors.initials: F
authors.lastname: Schick
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism; D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D005260:Female; D006801:Humans; D007866:Leg; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism / Q000502:physiology*; D012044:Regression Analysis; D018709:Statistics, Nonparametric