Assessment of glutamate and glutamine contribution to in vivo N-acetylaspartate quantification in human brain by 1H-magnetic resonance spectroscopy

✍ Scribed by Valeria Clementi; Caterina Tonon; Raffaele Lodi; Emil Malucelli; Bruno Barbiroli; Stefano Iotti

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 157 KB
• Volume: 54
• Category: Article
• ISSN: 0740-3194
• DOI: 10.1002/mrm.20703

✦ Synopsis

Abstract

N‐Acetylaspartate (NAA) is one of the most important metabolites detectable by brain ^1^H‐MRS being considered an index of neuronal integrity. At the low magnetic field used in most clinical settings β,γ‐glutamate/glutamine (Glx) resonances are very close and partially overlap the methyl‐NAA resonance interfering with NAA quantification especially at low TE and in the presence of increased Glx signals. NAA overestimation due to Glx on a set of model solutions containing NAA, glutamate, and glutamine in variable amounts was evaluated and the result tested in vivo in six healthy controls and five age‐ and sex‐matched patients with hepatic encephalopathy (HE), the latter having an increased Glx content. A method to assess in vivo the NAA overestimation caused by Glx is proposed. A perfect match was obtained between the assessment of Glx contamination on the NAA of healthy controls and that obtained on the model solutions. However, a substantial difference in NAA overestimation was found between controls and HE patients that cannot be explained by our model. An interpretative hypothesis is provided. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.