title: Sodium quantification in the spinal cord at 3T.
abstract: OBJECTIVE
  Sodium channels are involved in neuronal function and therefore methods to assess tissue sodium concentration in vivo are exceptionally appealing. Recently there has been a renewed interest for brain sodium magnetic resonance imaging (MRI), thanks to higher magnetic field strength scanners. However, sodium measures in the spinal cord are lacking due to major technical challenges. Here we propose for the first time a clinically feasible non-invasive method for quantifying sodium in the spine using magnetic resonance spectroscopy.
  
  
  METHODS
  Sodium spectra from the cervical cord were collected using image selected in vivo spectroscopy (∼14 min scan time) and quantified using a reference phantom.
  
  
  RESULTS
  The sodium magnetic resonance spectroscopy measures provided in vivo concentration estimates of 31.2±2.4 mM. Repeat scans showed good reproducibility with a coefficient of variation of <6%.
  
  
  CONCLUSIONS
  Proposed here for the first time is a fast non-invasive technique to quantify total sodium in the spinal cord in vivo. This newly proposed technique has a great potential for translation into clinic, thanks to its simplicity.
authors.affiliation: NMR Research Unit, Queen Square MS Centre, Department of Neuroinflammation, UCL Institute of Neurology, London, UK. b.solanky@ucl.ac.uk
authors.forename: Bhavana S
authors.initials: BS
authors.lastname: Solanky
authors.forename: Frank
authors.initials: F
authors.lastname: Riemer
authors.forename: Xavier
authors.initials: X
authors.lastname: Golay
authors.forename: Claudia A M
authors.initials: CA
authors.lastname: Wheeler-Kingshott
mesh_terms: D000328:Adult; D000465:Algorithms; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D057054:Molecular Imaging / Q000379:methods*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012964:Sodium / Q000032:analysis / Q000378:metabolism*; D012975:Sodium Isotopes / Q000493:pharmacokinetics; D013116:Spinal Cord / Q000033:anatomy & histology* / Q000378:metabolism*; D014018:Tissue Distribution
chemical_list: D019275:Radiopharmaceuticals; D012975:Sodium Isotopes; D012964:Sodium