title: Proton magnetic resonance spectroscopy of brain-stem lesions.
abstract: The imaging findings of brain-stem lesions are often nonspecific and histological diagnosis is limited because of fear of complications associated with biopsy. A noninvasive method for tissue characterization is therefore highly desirable. We undertook a review of proton magnetic resonance spectroscopy (MRS) of patients with solitary brain-stem lesions to determine if MRS could characterize them. We carried out single- or multivoxel proton MRS using long echo times (135 or 270 ms) on 34 patients with solitary brain-stem lesions. We analyzed the following peaks: choline (Cho), creatine (Cr), N-acetylaspartate (NAA), and lipids/lactate (Lip) and calculated peak height ratios for Cho/Cr, NAA/Cr and Lip/Cr. The results were compared with histology in nine patients and with the presumptive diagnosis in 25. We also performed single-voxel proton MRS on the brain stem of five normal volunteers. There were differences in all ratios between controls and the patients with neoplastic and non-neoplastic lesions: Cho/Cr was low in non-neoplastic and high in neoplastic lesions (control: 1.8+/-0.1; non-neoplastic: 1.4+/-0.2; neoplastic: 2.0+/-0.2); NAA/Cr was low in non-neoplastic, and lower in neoplastic lesions (control: 2.3+/-0.1; non-neoplastic: 1.4+/-0.2; neoplastic: 1.2+/-0.1), and Lip/Cr was elevated in both neoplastic and non-neoplastic lesions (control: 0.04+/-0.02; nonneoplastic: 1.9+/-0.7; neoplastic:1.9+/-0.7).
authors.affiliation: Department of Radiology, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7510, USA.
authors.forename: J K
authors.initials: JK
authors.lastname: Smith
authors.forename: A
authors.initials: A
authors.lastname: Londono
authors.forename: M
authors.initials: M
authors.lastname: Castillo
authors.forename: L
authors.initials: L
authors.lastname: Kwock
mesh_terms: D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D001921:Brain / Q000378:metabolism; D001923:Brain Chemistry; D001927:Brain Diseases / Q000175:diagnosis*; D001933:Brain Stem / Q000473:pathology*; D020295:Brain Stem Neoplasms / Q000175:diagnosis*; D002794:Choline / Q000378:metabolism; D003401:Creatine / Q000378:metabolism; D005260:Female; D006801:Humans; D050356:Lipid Metabolism; D009682:Magnetic Resonance Spectroscopy; D008297:Male
chemical_list: D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline