title: Measurement of initial N-acetyl aspartate concentration by magnetic resonance spectroscopy and initial infarct volume by MRI predicts outcome in patients with middle cerebral artery territory infarction.
abstract: OBJECTIVE
  (1)H MR spectroscopy can be used to study biochemical changes occurring in the brain in stroke. We used it to examine the relationship between metabolite concentration (N-acetyl aspartate [NAA], lactate, cholines and creatines), size of infarct, clinical deficit, and 3-month clinical outcome in patients with middle cerebral artery (MCA) territory infarction.
  
  
  METHODS
  Thirty-one patients with acute MCA territory infarction were recruited within 72 hours of the onset of symptoms. Single-voxel short echo time stimulated echo acquistion mode spectroscopy was used to obtain metabolite data from the infarct core. Metabolite concentrations were determined with use of variable projection time domain-fitting analysis. Infarct size was determined with T2-weighted images. Patient outcome groups at 3 months were "independent," "dependent," or "dead."
  
  
  RESULTS
  All patients (100%; 95% CI 75% to 100%) who had an infarct >70 mL did poorly. Eighteen of 20 patients (90%; 95% CI 68% to 99%) with a core NAA concentration <7 mmol/L did poorly at 3 months, whereas 7 of 11 patients (64%; 95% CI 31% to 89%) with an initial NAA concentration >7 mmol/L did well. Combining these results showed that all patients who had an initial infarct volume >70 mL did poorly, irrespective of the NAA concentration. Of those patients with infarcts <70 mL, those who had a core NAA concentration >7 mmol/L did well (88%; 95% CI 47% to 100%), whereas those with a lower NAA concentration did poorly (80%; 95% CI 44% to 97%). There was no association between other metabolite concentrations and outcome.
  
  
  CONCLUSIONS
  Infarct volume and NAA concentration can together predict clinical outcome in MCA infarction in humans.
authors.affiliation: Division of Clinical Neuroscience, CRC Biomedical Magnetic Resonance Research Group, Department of Public Health Medicine, London, UK.
authors.forename: A C
authors.initials: AC
authors.lastname: Pereira
authors.forename: D E
authors.initials: DE
authors.lastname: Saunders
authors.forename: V L
authors.initials: VL
authors.lastname: Doyle
authors.forename: J M
authors.initials: JM
authors.lastname: Bland
authors.forename: F A
authors.initials: FA
authors.lastname: Howe
authors.forename: J R
authors.initials: JR
authors.lastname: Griffiths
authors.forename: M M
authors.initials: MM
authors.lastname: Brown
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D015415:Biomarkers; D001921:Brain / Q000098:blood supply / Q000378:metabolism* / Q000473:pathology; D002536:Cerebral Arteries / Q000378:metabolism; D002544:Cerebral Infarction / Q000175:diagnosis* / Q000378:metabolism; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; D001224:Aspartic Acid; C000179:N-acetylaspartate