Cortical N-acetyl aspartate is a predictor of long-term clinical disability in multiple sclerosis.

OBJECTIVE: To evaluate the prognostic value of the cortical N-acetyl aspartate to creatine ratio (NAA/Cr) in early relapsing-remitting multiple sclerosis (RRMS). METHODS: Sixteen patients with newly diagnosed RRMS were studied by serial MRI and MR spectroscopic imaging (MRSI) once every 6 months for 24 months. Clinical examinations, including the expanded disability status scale (EDSS), were performed at baseline, month 24, and at year 7. RESULTS: Baseline cortical NAA/Cr correlated inversely with EDSS at month 24 (r  =  -0·61, P < 0·05), and patients with EDSS ≧ 4 had a lower baseline cortical NAA/Cr compared to those with EDSS less than 4 (P < 0·05). Baseline cortical NAA/Cr also correlated inversely with EDSS at the 7-year follow-up (r  =  -0·56, P < 0·05), and patients with EDSS ≧ 4 had a lower baseline cortical NAA/Cr compared to those with EDSS less than 4 (P < 0·05). Baseline brain parenchymal fraction (BPF) correlated inversely with EDSS at month 24 (r  =  -0·61, P < 0·05), but not with EDSS at year 7. DISCUSSION: Cortical NAA/Cr in early RRMS correlated with clinical disability after 2 and 7 years and may be used as a predictor of long-term disease outcome.

[Proton magnetic resonance spectroscopy in the evaluation of cognitive disturbances]. / Protonmagnetisk resonans-spektroskopi til vurdering af kognitive forstyrrelser.

Magnetic resonance spectroscopy can detect metabolic changes in the brain, including changes in N-acetyl aspartate, a metabolite generally believed to be a marker of neuronal integrity. The correlations between metabolic changes and cognitive status in normal subjects and in a range of neurological and psychiatric disorders are reviewed. Magnetic resonance spectroscopy seems to be a way to monitor the efficacy of existing and new treatments to prevent the development of cognitive deficits in a number of diseases.