title: Significant differences in proton trimethyl ammonium signals between human gastrocnemius and soleus muscle.
abstract: OBJECTIVE
  To study the apparent heterogeneous characteristics of trimethyl ammonium (TMA) in healthy human muscles at rest, and to illustrate the importance of establishing the baseline characteristics of proton metabolites in muscles with a West Nile patient.
  
  
  METHODS
  Point-resolved spectroscopy (PRESS) magnetic resonance spectroscopy imaging (MRSI) with lipid suppression and optional outer-volume presaturation were used to acquire 1H spectra of human muscles at rest at 1.5 Tesla. A total of 28 subjects (27 normal volunteers and 1 patient with West Nile disease) between the ages of 22 and 76 participated in the study.
  
  
  RESULTS
  The apparent T2 values of TMA for soleus and gastrocnemius muscles in normal volunteers are 180 +/- 50 and 80 +/- 20 msec, respectively. This difference has profound effects on the apparent spectral pattern of 1H metabolites. The TMA/total creatine (tCr) spectral pattern of the soleus muscle of a West Nile patient resembles that of gastrocnemius muscle of healthy volunteers.
  
  
  CONCLUSIONS
  There are significant differences in the apparent T2 values of TMA between healthy soleus and gastrocnemius muscles at rest. It is important to establish the baseline characteristics of proton metabolites before clinical or physiological studies can be performed.
authors.affiliation: Department of Radiology, Wayne State University, Detroit, Michigan, USA. jhu@med.wayne.edu
authors.forename: Jiani
authors.initials: J
authors.lastname: Hu
authors.forename: Yang
authors.initials: Y
authors.lastname: Xia
authors.forename: Yimin
authors.initials: Y
authors.lastname: Shen
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Chun S
authors.initials: CS
authors.lastname: Zuo
authors.forename: Yang
authors.initials: Y
authors.lastname: Xuan
authors.forename: Quan
authors.initials: Q
authors.lastname: Jiang
mesh_terms: D000328:Adult; D000368:Aged; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism*; D011522:Protons; D000644:Quaternary Ammonium Compounds / Q000378:metabolism*; D014901:West Nile Fever / Q000378:metabolism*
chemical_list: D011522:Protons; D000644:Quaternary Ammonium Compounds