Institute of Diagnostic and Interventional Neuroradiology, Hannover Medical School, Hannover, Germany.
Department of Radiology, University of Miami School of Medicine, Miami, FL, USA.
Clin Neuroradiol. 2020 Jun;30(2):251-261. doi: 10.1007/s00062-018-00757-x. Epub 2019 Jan 18.
The aim of this study was to compare a recently established whole brain MR spectroscopic imaging (wbMRSI) technique using spin-echo planar spectroscopic imaging (EPSI) acquisition and the Metabolic Imaging and Data Analysis System (MIDAS) software package with single voxel spectroscopy (SVS) technique and LCModel analysis for determination of relative metabolite concentrations in aging human brain.
A total of 59 healthy subjects aged 20-70 years (n ≥ 5 per age decade for each gender) underwent a wbEPSI scan and 3 SVS scans of a 4 ml voxel volume located in the right basal ganglia, occipital grey matter and parietal white matter. Concentration ratios to total creatine (tCr) for N‑acetylaspartate (NAA/tCr), total choline (tCho/tCr), glutamine (Gln/tCr), glutamate (Glu/tCr) and myoinositol (mI/tCr) were obtained both from EPSI and SVS acquisitions with either LCModel or MIDAS. In addition, an aqueous phantom containing known metabolite concentrations was also measured.
Metabolite concentrations obtained with wbMRSI and SVS were comparable and consistent with those reported previously. Decreases of NAA/tCr and increases of line width with age were found with both techniques, while the results obtained from EPSI acquisition revealed generally narrower line widths and smaller Cramer-Rao lower bounds than those from SVS data.
The wbMRSI could be used to estimate metabolites in vivo and in vitro with the same reliability as using SVS, with the main advantage being the ability to determine metabolite concentrations in multiple brain structure simultaneously in vivo. It is expected to be widely used in clinical diagnostics and neuroscience.
本研究旨在比较一种新建立的基于自旋回波平面波谱成像（EPSI）采集和代谢成像与数据分析系统（MIDAS）软件包的全脑磁共振波谱成像（wbMRSI）技术与单体素波谱（SVS）技术和 LCModel 分析，以确定老化人脑的相对代谢物浓度。
共 59 名健康受试者（年龄 20-70 岁；每个性别各年龄组至少 5 名）接受了 wbEPSI 扫描和右基底节、枕叶灰质和顶叶白质 4ml 体素容积的 3 次 SVS 扫描。使用 LCModel 或 MIDAS 从 EPSI 和 SVS 采集获得 N-乙酰天冬氨酸（NAA/tCr）、总胆碱（tCho/tCr）、谷氨酰胺（Gln/tCr）、谷氨酸（Glu/tCr）和肌醇（mI/tCr）与总肌酸（tCr）的浓度比。此外，还测量了含有已知代谢物浓度的水溶液。
wbMRSI 和 SVS 获得的代谢物浓度与之前报道的相似且一致。两种技术均发现 NAA/tCr 降低和线宽随年龄增加，而 EPSI 采集的结果显示，线宽普遍比 SVS 数据窄，Cramer-Rao 下限更小。
wbMRSI 可用于在体内和体外以与 SVS 相同的可靠性估计代谢物，其主要优势在于能够同时在体内确定多个脑结构的代谢物浓度。它有望在临床诊断和神经科学中得到广泛应用。
