title: 3T 1H-MR spectroscopy in grading of cerebral gliomas: comparison of short and intermediate echo time sequences.
abstract: OBJECTIVE
  Echo time (TE) can have a large influence on the spectra in proton MR spectroscopy ((1)H-MR spectroscopy). The purpose of this study was to comparatively assess the diagnostic value of 3T single-voxel (1)H-MR spectroscopy with short or intermediate TEs in grading cerebral gliomas.
  
  
  METHODS
  Single voxel (1)H-MR spectroscopy was performed at 3T in 35 patients with cerebral glioma. The spectra were obtained with both short (35 ms) and intermediate TEs (144 ms). Metabolite ratios of choline (Cho)/creatine (Cr), Cho/N-acetylaspartate (NAA), lipid and lactate (LL)/Cr and myo-inositol (mIns)/Cr were calculated and compared between short and intermediate TEs in each grade. After receiver operating characteristic curve analysis, diagnostic accuracy for each TE in differentiating high-grade glioma from low-grade glioma was compared.
  
  
  RESULTS
  At short TE, Cho/Cr and Cho/NAA ratios were significantly lower, and LL/Cr and mIns/Cr were significantly higher, compared with those at intermediate TE, regardless of tumor grade. Lactate inversion at intermediate TE was found in only 2 patients. At both TEs, there were significant differences in Cho/Cr and LL/Cr ratios between low- and high-grade gliomas. Diagnostic accuracy was slightly higher at short TE alone or combined with intermediate TE than intermediate TE alone (85.7% versus 82.9%).
  
  
  CONCLUSIONS
  Metabolite ratios were significantly different between short and intermediate TE. Cho/Cr and LL/Cr ratios at either TE were similarly useful in differentiating high-grade gliomas from low-grade gliomas. If only a single spectroscopic sequence can be acquired, short TE seems preferable because of poor lactate inversion at intermediate TE on 3T single-voxel (1)H-MR spectroscopy.
authors.affiliation: Department of Radiology, Seoul Municipal Boramae Hospital, Seoul, Korea.
authors.forename: J-h
authors.initials: JH
authors.lastname: Kim
authors.forename: K-H
authors.initials: KH
authors.lastname: Chang
authors.forename: D G
authors.initials: DG
authors.lastname: Na
authors.forename: I C
authors.initials: IC
authors.lastname: Song
authors.forename: B J
authors.initials: BJ
authors.lastname: Kwon
authors.forename: M H
authors.initials: MH
authors.lastname: Han
authors.forename: K
authors.initials: K
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000032:analysis; D001932:Brain Neoplasms / Q000175:diagnosis*; D002794:Choline / Q000032:analysis; D003401:Creatine / Q000032:analysis; D017352:Echo-Planar Imaging / Q000379:methods; D005260:Female; D005910:Glioma / Q000175:diagnosis*; D006801:Humans; D006859:Hydrogen; D007089:Image Enhancement / Q000379:methods; D007294:Inositol / Q000032:analysis; D007773:Lactates / Q000032:analysis; D008055:Lipids / Q000032:analysis; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010725:Phosphocreatine / Q000032:analysis; D013997:Time Factors
chemical_list: D007773:Lactates; D008055:Lipids; D010725:Phosphocreatine; D001224:Aspartic Acid; D007294:Inositol; D006859:Hydrogen; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline