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

• DOI: 10.1161/01.str.30.8.1577
• Publication Date: 2011-06-17T20:08:03Z
• Authors: Anthony C. Pereira; Dawn E. Saunders; Victoria L. Doyle; J. Martin Bland; Franklyn A. Howe; John R. Griffiths; Martin M. Brown
• Keywords: Adult; Aged, 80 and over; Observer Variation; Aspartic Acid; Brain; Cerebral Infarction; Cerebral Arteries; Middle Aged; Magnetic Resonance Imaging; Severity of Illness Index; 03 medical and health sciences; 0302 clinical medicine; Predictive Value of Tests; Humans; Biomarkers; Aged; Follow-Up Studies

Background and Purpose — 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.