De Stefano N, Mortilla M, Federico A
Neurometabolic Unit, Institute of Neurological Sciences, University of Siena, Italy.
Ital J Neurol Sci. 1999;20(5 Suppl):S258-64. doi: 10.1007/s100729970008.
Proton magnetic resonance spectroscopy (MRS) allows accurate and noninvasive biochemical assay of living tissues. In vivo measurements provided by MRS have greatly enhanced our understanding of the pathophysiology of dementia. Increases in choline and myo-inositol (markers of membrane turnover) have been demonstrated in several studies on patients with Alzheimer's disease (AD), suggesting the presence of a significant cellular membrane (and glial) pathology in this disorder. Large decreases in brain N-acetylaspartate (NAA) (a marker of neuroaxonal integrity) are commonly seen in AD as well as in other forms of dementia in cerebral gray and white matter, indicating the presence of significant axonal damage. Since greater NAA decreases have been demonstrated in brains of patients with clinically more severe disease, NAA could provide an index relevant to patients' clinical status. Brain metabolic changes can be independent of abnormalities detected by conventional magnetic resonance imaging (MRI), since proton MRS may show a normal metabolic pattern in patients with mild neurological impairment and severe MRI abnormalities. However, quantitative measurements of regional brain volumes can be useful in the diagnosis of dementia. Thus, proton MRS, alone or combined with new quantitative magnetic resonance techniques, can provide sensitive indices able to monitor disease progresson or effects of drug therapy.
质子磁共振波谱（MRS）可对活体组织进行准确且无创的生化分析。MRS提供的体内测量极大地增进了我们对痴呆症病理生理学的理解。在多项针对阿尔茨海默病（AD）患者的研究中，已证实胆碱和肌醇（膜更新的标志物）增加，这表明该疾病存在显著的细胞膜（及神经胶质）病变。在AD以及其他形式的痴呆症患者的脑灰质和白质中，通常可见脑N-乙酰天门冬氨酸（NAA）（神经轴突完整性的标志物）大幅下降，这表明存在显著的轴突损伤。由于在临床病情更严重的患者大脑中已证实NAA下降幅度更大，NAA可提供与患者临床状况相关的指标。脑代谢变化可能独立于传统磁共振成像（MRI）检测到的异常情况，因为质子MRS可能在轻度神经功能损害且MRI异常严重的患者中显示正常的代谢模式。然而，区域脑容量的定量测量在痴呆症诊断中可能有用。因此，质子MRS单独使用或与新的定量磁共振技术结合使用，可提供能够监测疾病进展或药物治疗效果的敏感指标。
