COMBINED MAGNETIC-RESONANCE-IMAGING AND PROTON MAGNETIC-RESONANCE SPECTROSCOPY OF PATIENTS WITH ACUTE STROKE

Background and Purpose: The prospect for a therapeutic window for treatment of ischemic stroke encourages the noninvasive investigation of metabolic changes in acute ischemia. Recently, localized proton spectroscopy became available at 1.5-T magnetic resonance systems. In this study we evaluated the usefulness of combined magnetic resonance imaging and spectroscopy on the diagnosis of acute and chronic infarctions. Methods: Combined magnetic resonance imaging and spectroscopy investigations were carried out with a 1.5-T system in 16 volunteers, eight patients with chronic infarction (>8 months), and 10 patients with acute ischemic stroke (<8 hours). We used a stimulated echo sequence to acquire localized spectra from image-guided volumes of interest (16-27 ml). Results: There were no significant interindividual differences of choline, creatine, phosphocreatine, and N-acetyl aspartate resonances in the spectra from volunteers. In chronic infarctions, N-acetyl aspartate was decreased in relation to choline. Acute ischemic infarctions were characterized by decreased N-acetyl aspartate resonances and elevation of lactate. Conclusions: The study demonstrates the feasibility of proton spectroscopy in stroke patients. Metabolic alterations in ischemic tissue can be monitored and can distinguish acute from chronic lesions.