title: A comparison of two post-processing analysis methods to quantify cerebral metabolites measured via proton magnetic resonance spectroscopy in HIV disease.
abstract: OBJECTIVE
  Non-invasive biomarkers to monitor cerebral function in treated human immunodeficiency virus (HIV) disease are required. Cerebral metabolite ratios (CMRs) measured by proton-MR spectroscopy ((1)H-MRS) are a potential biomarker. Here, we compare two post-processing software packages to quantify CMRs.
  
  
  METHODS
  Cerebral (1)H-MRS data from 11 HIV-positive subjects before and after antiretroviral therapy intensification with maraviroc were quantified using a java-based version of the MR user interface package (jMRUI) and the totally automatic robust quantitation in nuclear MR (TARQUIN). (1)H-MRS data included N-acetylaspartate (NAA), creatine (Cr), choline (Cho) and myo-inositol (mI) from three cerebral locations. Differences in quantification and clinical associations of CMRs measured by the two packages were evaluated.
  
  
  RESULTS
  Mean CMRs were generally lower when measured by TARQUIN than by jMRUI (NAA/Cr, Cho/Cr, mI/Cr ratios of 1.78, 0.83, 0.81 for jMRUI, and 1.27, 0.25, 0.81 for TARQUIN). Longitudinal changes were observed in CMRs in the basal ganglia voxel although these changes were not statistically significant [+7.1% (p = 0.18), +0.0% (p = 0.91) and -6.6% (p = 0.61) and +14.8% (p = 0.18), +17.9% (p = 0.07) and +34.8% (p = 0.17) for NAA/Cr, Cho/Cr and mI/Cr ratios measured by TARQUIN and jMRUI, respectively]. Plasma maraviroc concentration was associated with a decrease in mI/Cr ratio measured via TARQUIN (p = 0.049).
  
  
  CONCLUSIONS
  Although CMRs differed when quantified by jMRUI vs TARQUIN, these differences were consistently observed across three cerebral locations, and clinical associations were evident by both methods.
  
  
  CONCLUSIONS
  TARQUIN and jMRUI are viable options to use in the post-processing of cerebral MRS data acquired in HIV disease.
authors.affiliation: Division of Infectious Diseases, Winston Churchill Wing, St Mary's Campus, Imperial College, London, UK.
authors.forename: Joseph
authors.initials: J
authors.lastname: Scott
authors.affiliation: Division of Infectious Diseases, Winston Churchill Wing, St Mary's Campus, Imperial College, London, UK.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Underwood
authors.affiliation: Division of Infectious Diseases, Winston Churchill Wing, St Mary's Campus, Imperial College, London, UK.
authors.forename: Lucy J
authors.initials: LJ
authors.lastname: Garvey
authors.affiliation: Division of Infectious Diseases, Winston Churchill Wing, St Mary's Campus, Imperial College, London, UK.
authors.forename: Borja
authors.initials: B
authors.lastname: Mora-Peris
authors.affiliation: Division of Infectious Diseases, Winston Churchill Wing, St Mary's Campus, Imperial College, London, UK.
authors.forename: Alan
authors.initials: A
authors.lastname: Winston
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D001921:Brain / Q000378:metabolism*; D001927:Brain Diseases / Q000175:diagnosis*; D065100:CCR5 Receptor Antagonists / Q000097:blood / Q000627:therapeutic use; D003510:Cyclohexanes / Q000097:blood / Q000627:therapeutic use; D015658:HIV Infections / Q000175:diagnosis* / Q000188:drug therapy; D006801:Humans; D000077592:Maraviroc; D066244:Proton Magnetic Resonance Spectroscopy / Q000379:methods*; D014230:Triazoles / Q000097:blood / Q000627:therapeutic use
chemical_list: D015415:Biomarkers; D065100:CCR5 Receptor Antagonists; D003510:Cyclohexanes; D014230:Triazoles; D000077592:Maraviroc