title: Proton MR spectroscopy of tumefactive demyelinating lesions.
abstract: OBJECTIVE
  Tumefactive demyelinating lesions (TDLs) can simulate intracranial neoplasms in clinical presentation and MR imaging appearance, and surgical biopsy is often performed in suspected tumors. Proton MR spectroscopy has been applied in assessing various intracranial diseases and is increasingly used in diagnosis and clinical management. Our purpose was to determine if multivoxel proton MR spectroscopy can be used to differentiate TDLs and high-grade gliomas.
  
  
  METHODS
  Conventional MR images, proton MR spectra, and medical records were retrospectively reviewed in six patients with TDLs diagnosed by means of biopsy or by documented clinical improvement, with or without supporting laboratory testing and follow-up imaging. Proton MR spectra of 10 high-grade gliomas with similar conventional MR imaging appearances were used for comparison. In contrast-enhancing, central, and perilesional areas of each lesion, peak heights of N-acetylaspartate (NAA), choline (Cho), and creatine (Cr) were measured and the lactate peak noted. Cho/Cr and NAA/Cr ratios of corresponding regions in TDLs and gliomas were compared.
  
  
  RESULTS
  No significant differences in mean Cho/Cr ratios were found in the corresponding contrast-enhancing, central, or perilesional areas of TDLs and gliomas. The mean central-region NAA/Cr ratio in gliomas was significantly lower than that of TDLs, but mean NAA/Cr ratios in other regions were not significantly different. A lactate peak was identified in four of six TDLs and three of 10 gliomas.
  
  
  CONCLUSIONS
  In the cases examined, the NAA/Cr ratio in the central region of TDLs and high-grade gliomas differed significantly. However, overall metabolite profiles of both lesions were similar; this finding emphasizes the need for the cautious interpretation of spectroscopic findings.
authors.affiliation: Department of Radiology, New York University Medical Center, MRI Center, NY, USA.
authors.forename: Amit M
authors.initials: AM
authors.lastname: Saindane
authors.forename: Soonmee
authors.initials: S
authors.lastname: Cha
authors.forename: Meng
authors.initials: M
authors.lastname: Law
authors.forename: Xiaonan
authors.initials: X
authors.lastname: Xue
authors.forename: Edmond A
authors.initials: EA
authors.lastname: Knopp
authors.forename: David
authors.initials: D
authors.lastname: Zagzag
mesh_terms: D000328:Adult; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D001921:Brain / Q000378:metabolism / Q000473:pathology*; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000378:metabolism; D003401:Creatine / Q000378:metabolism; D003711:Demyelinating Diseases / Q000175:diagnosis* / Q000378:metabolism; D003937:Diagnosis, Differential; D005260:Female; D005910:Glioma / Q000175:diagnosis* / Q000378:metabolism; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies
chemical_list: D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine