title: In vivo 1D and 2D correlation MR spectroscopy of the soleus muscle at 7T.
abstract: OBJECTIVE
  This study aims to (1) undertake and analyse 1D and 2D MR correlation spectroscopy from human soleus muscle in vivo at 7T, and (2) determine T1 and T2 relaxation time constants at 7T field strength due to their importance in sequence design and spectral quantitation.
  
  
  METHODS
  Six healthy, male volunteers were consented and scanned on a 7T whole-body scanner (Siemens AG, Erlangen, Germany). Experiments were undertaken using a 28cm diameter detunable birdcage coil for signal excitation and an 8.5cm diameter surface coil for signal reception. The relaxation time constants, T1 and T2 were recorded using a STEAM sequence, using the 'progressive saturation' method for the T1 and multiple echo times for T2. The 2D L-Correlated SpectroscopY (L-COSY) method was employed with 64 increments (0.4ms increment size) and eight averages per scan, with a total time of 17min.
  
  
  RESULTS
  T1 and T2 values for the metabolites of interest were determined. The L-COSY spectra obtained from the soleus muscle provided information on lipid content and chemical structure not available, in vivo, at lower field strengths. All molecular fragments within multiple lipid compartments were chemically shifted by 0.20-0.26ppm at this field strength. 1D and 2D L-COSY spectra were assigned and proton connectivities were confirmed with the 2D method.
  
  
  CONCLUSIONS
  In vivo 1D and 2D spectroscopic examination of muscle can be successfully recorded at 7T and is now available to assess lipid alterations as well as other metabolites present with disease. T1 and T2 values were also determined in soleus muscle of male healthy volunteers.
authors.affiliation: Centre for Clinical Spectroscopy, Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, 4 Blackfan St., H.I.M., 8th Floor, Boston, MA 02115, USA. saad.ramadan@gmail.com
authors.forename: Saadallah
authors.initials: S
authors.lastname: Ramadan
authors.forename: Eva-Maria
authors.initials: EM
authors.lastname: Ratai
authors.forename: Lawrence L
authors.initials: LL
authors.lastname: Wald
authors.forename: Carolyn E
authors.initials: CE
authors.lastname: Mountford
mesh_terms: D000328:Adult; D003401:Creatine / Q000032:analysis*; D006801:Humans; D008055:Lipids / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D018482:Muscle, Skeletal / Q000737:chemistry*; D012680:Sensitivity and Specificity
chemical_list: D008055:Lipids; D003401:Creatine