title: Fractional anisotropy values of calf muscles in normative state after exercise: preliminary results.
abstract: OBJECTIVE
  We measured fractional anisotropy (FA) of calf muscles from diffusion tensor (DT) images from simultaneous scanning of bilateral calves and determined changes in values after unilateral exercise loading.
  
  
  METHODS
  We obtained DT images of both calves of 10 healthy male volunteers and measured FA of the anterior tibialis, gastrocnemius, and soleus muscles. Two of the ten were subjected to loaded exercise in their right calves; we recorded FA values immediately after exercise and 24 hours, 72 hours, and 1 week later.
  
  
  RESULTS
  At rest, the mean FA values of the 20 calves were 0.63+/-0.02 in the anterior tibialis, 0.56+/-0.05 in the gastrocnemius, and 0.57+/-0.04 in the soleus muscles. The differences were statistically significant (P<0.001) by analysis of variance (ANOVA), and differences between anterior tibialis and gastrocnemius (corrected P<0.01) and anterior tibialis and soleus (corrected P<0.01) muscles were significant by Bonferroni post hoc test. The FA values of the exercise-loaded soleus and gastrocnemius muscles of the 2 volunteers decreased just after exercise but gradually recovered to the baseline after one week.
  
  
  CONCLUSIONS
  Our method may be useful for assessing minimal muscle damage related to muscle fatigue.
authors.affiliation: Department of Radiology, Institute of Clinical Medicine, University of Tsukuba Hospital, Tsukuba, Ibaraki, Japan. yokamoto@md.tsukuba.ac.jp
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Okamoto
authors.forename: Akira
authors.initials: A
authors.lastname: Kunimatsu
authors.forename: Soichiro
authors.initials: S
authors.lastname: Miki
authors.forename: Masashi
authors.initials: M
authors.lastname: Shindo
authors.forename: Mamoru
authors.initials: M
authors.lastname: Niitsu
authors.forename: Manabu
authors.initials: M
authors.lastname: Minami
mesh_terms: D000328:Adult; D016880:Anisotropy; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005080:Exercise Test; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007866:Leg / Q000502:physiology; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018763:Muscle Fatigue / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D010865:Pilot Projects