Magnetic Resonance Spectroscopy (MRS) allows for the non-invasive quantification of neurochemicals and has the potential to differentiate between the pathologically distinct diseases, multiple sclerosis (MS) and AQP4Ab-positive neuromyelitis optica spectrum disorder (AQP4Ab-NMOSD). In this study we characterised the metabolite profiles of brain lesions in 11 MS and 4 AQP4Ab-NMOSD patients using an optimised MRS methodology at ultra-high field strength (7T) incorporating correction for T2 water relaxation differences between lesioned and normal tissue. MS metabolite results were in keeping with the existing literature: total NAA was lower in lesions compared to normal appearing brain white matter (NAWM) with reciprocal findings for Inositol. An unexpected subtlety revealed by our technique was that total NAA differences were driven by NAA-glutamate (NAAG), a ubiquitous CNS molecule with functions quite distinct from NAA though commonly quantified together with NAA in MRS studies as total NAA. Surprisingly, AQP4Ab-NMOSD showed no significant differences for total NAA, NAA, NAAG or Inositol between lesion and NAWM sites, nor were there any differences between MS and AQP4Ab-NMOSD for a priori hypotheses. Post-hoc testing did however reveal greater total NAA in MS compared to AQP4Ab-NMOSD NAWM. Post-hoc testing also revealed a significant correlation between NAWM Ins:NAA and disability (as measured by EDSS) for disease groups combined, driven by the AP4Ab-NMOSD group. Utilising an optimised MRS methodology, our study highlights some under-explored subtleties in MRS profiles, such as the absence of Inositol concentration differences in AQP4Ab-NMOSD brain lesions versus NAWM and the important influence of NAAG differences between lesions and normal appearing white matter in MS.

中文翻译：

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最佳的1H-MRS技术在7T：慢性多发性硬化症和视神经脊髓炎的大脑病变和正常出现的脑组织的原理证明。

磁共振波谱（MRS）允许对神经化学物质进行非侵入式定量分析，并具有区分病理学上不同的疾病，多发性硬化症（MS）和AQP4Ab阳性神经脊髓炎性视神经频谱疾病（AQP4Ab-NMOSD）的潜力。在这项研究中，我们使用优化的MRS方法在超高场强度（7T）上结合了病变组织和正常组织之间T2水弛豫差异的校正，对11名MS和4名AQP4Ab-NMOSD患者脑损伤的代谢产物进行了表征。MS代谢物的结果与现有文献一致：与正常出现的脑白质（NAWM）相比，病变中的总NAA更低，肌醇的发现也相反。我们的技术揭示了一个意想不到的微妙之处，即总NAA差异是由NAA-谷氨酸（NAAG）驱动的，NAAG是一种普遍存在的CNS分子，其功能与NAA完全不同，尽管在MRS研究中通常与NAA一起量化为总NAA。出人意料的是，AQP4Ab-NMOSD在病变部位和NAWM部位之间的总NAA，NAA，NAAG或肌醇没有显着差异，对于先验假设，MS和AQP4Ab-NMOSD之间也没有任何差异。然而，事后测试确实显示出MS中的总NAA高于AQP4Ab-NMOSD NAWM。事后测试还显示，在由AP4Ab-NMOSD组驱动的疾病合并组中，NAWM Ins：NAA与残疾（由EDSS测量）之间存在显着相关性。利用优化的MRS方法，我们的研究突出显示了MRS配置文件中一些尚未充分开发的细微之处，