title: Neurochemistry of brain lesions determined by spectroscopic imaging in systemic lupus erythematosus.
abstract: OBJECTIVE
  The significance and etiology of focal brain lesions in systemic lupus erythematosus (SLE) are unknown. Our purpose was to determine whether the neurochemistry of focal lesions and normal appearing brain tissues in SLE were consistent with neuronal loss, demyelination, or ischemia.
  
  
  METHODS
  Patients with SLE (n = 14) and controls (n = 13) were studied using magnetic resonance imaging (MRI) and spectroscopic imaging (SI) at 1.5 Tesla.
  
  
  RESULTS
  MRI detected fixed focal brain lesions (n = 16) and SI measured brain metabolites, including N-acetylaspartate (NAA), creatine (Cre), choline (Cho), and lactate (Lac). NAA/Cre of normal appearing brain was decreased in patients with SLE compared to controls: grey matter (1.74 +/- 0.16 vs 1.92 +/- 0.18; p = 0.01), occipital white matter (1.98 +/- 0.22 vs 2.23 +/- 0.16; p = 0.004), and periventricular white matter (2.00 +/- 0.23 vs 2.33 +/- 0.23; p = 0.001). Lesions were characterized by markedly decreased NAA/Cre relative to normal appearing tissues in the same patient (1.67 +/- 0.22 vs 1.88 +/- 0.14; p = 0.0002). Elevated Cho/Cre was observed in 25% of focal lesions and 21% of normal appearing tissues. No elevation of lactate was observed in lesions or normal appearing tissues.
  
  
  CONCLUSIONS
  SI detects focal and generalized brain abnormalities in SLE characterized by decreased NAA, elevated choline, and normal lactate. These findings are consistent with widespread neuronal injury and demyelination, but are not consistent with anaerobic metabolism.
authors.affiliation: Center for Non-Invasive Diagnosis and the Department of Neurosciences, University of New Mexico Health Sciences Center, Albuquerque 87131, USA.
authors.forename: W M
authors.initials: WM
authors.lastname: Brooks
authors.forename: A
authors.initials: A
authors.lastname: Sabet
authors.forename: W L
authors.initials: WL
authors.lastname: Sibbitt
authors.forename: P B
authors.initials: PB
authors.lastname: Barker
authors.forename: P C
authors.initials: PC
authors.lastname: van Zijl
authors.forename: J H
authors.initials: JH
authors.lastname: Duyn
authors.forename: C T
authors.initials: CT
authors.lastname: Moonen
mesh_terms: D000328:Adult; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000032:analysis; D015415:Biomarkers; D002552:Cerebral Ventricles / Q000737:chemistry; D002794:Choline / Q000032:analysis; D003401:Creatine / Q000032:analysis; D005260:Female; D006801:Humans; D019344:Lactic Acid / Q000032:analysis; D008180:Lupus Erythematosus, Systemic / Q000175:diagnosis* / Q000378:metabolism*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000737:chemistry; D009474:Neurons / Q000737:chemistry / Q000648:ultrastructure; D009778:Occipital Lobe / Q000737:chemistry* / Q000166:cytology
chemical_list: D015415:Biomarkers; D001224:Aspartic Acid; D019344:Lactic Acid; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline