利用全脑磁共振波谱成像和定量磁共振成像检测正常衰老对人脑代谢物浓度和微观结构的影响
Detection of Normal Aging Effects on Human Brain Metabolite Concentrations and Microstructure with Whole-Brain MR Spectroscopic Imaging and Quantitative MR Imaging.
作者信息
Eylers V V, Maudsley A A, Bronzlik P, Dellani P R, Lanfermann H, Ding X-Q
机构信息
From the Institute of Diagnostic and Interventional Neuroradiology (V.V.E., P.B., P.R.D., H.L., X.-Q.D.), Hannover Medical School, Hannover, Germany.
Department of Radiology (A.A.M.), University of Miami School of Medicine, Miami, Florida.
出版信息
AJNR Am J Neuroradiol. 2016 Mar;37(3):447-54. doi: 10.3174/ajnr.A4557. Epub 2015 Nov 12.
BACKGROUND AND PURPOSE
Knowledge of age-related physiological changes in the human brain is a prerequisite to identify neurodegenerative diseases. Therefore, in this study whole-brain (1)H-MRS was used in combination with quantitative MR imaging to study the effects of normal aging on healthy human brain metabolites and microstructure.
MATERIALS AND METHODS
Sixty healthy volunteers, 21-70 years of age, were studied. Brain maps of the metabolites NAA, creatine and phosphocreatine, and Cho and the tissue irreversible and reversible transverse relaxation times T2 and T2' were derived from the datasets. The relative metabolite concentrations and the values of relaxation times were measured with ROIs placed within the frontal and parietal WM, centrum semiovale, splenium of the corpus callosum, hand motor area, occipital GM, putamen, thalamus, pons ventral/dorsal, and cerebellar white matter and posterior lobe. Linear regression analysis and Pearson correlation tests were used to analyze the data.
RESULTS
Aging resulted in decreased NAA concentrations in the occipital GM, putamen, splenium of the corpus callosum, and pons ventral and decreased creatine and phosphocreatine concentrations in the pons dorsal and putamen. Cho concentrations did not change significantly in selected brain regions. T2 increased in the cerebellar white matter and decreased in the splenium of the corpus callosum with aging, while the T2' decreased in the occipital GM, hand motor area, and putamen, and increased in the splenium of the corpus callosum. Correlations were found between NAA concentrations and T2' in the occipital GM and putamen and between creatine and phosphocreatine concentrations and T2' in the putamen.
CONCLUSIONS
The effects of normal aging on brain metabolites and microstructure are region-dependent. Correlations between both processes are evident in the gray matter. The obtained data could be used as references for future studies on patients.
背景与目的
了解人类大脑中与年龄相关的生理变化是识别神经退行性疾病的前提条件。因此，在本研究中，全脑氢质子磁共振波谱（1H-MRS）与定量磁共振成像相结合，以研究正常衰老对健康人脑代谢物和微观结构的影响。
材料与方法
对60名年龄在21至70岁之间的健康志愿者进行了研究。从数据集中得出代谢物N-乙酰天门冬氨酸（NAA）、肌酸和磷酸肌酸以及胆碱（Cho）的脑图谱，以及组织不可逆和可逆横向弛豫时间T2和T2'。通过在额叶和顶叶白质、半卵圆中心、胼胝体压部、手部运动区、枕叶灰质、壳核、丘脑、脑桥腹侧/背侧以及小脑白质和后叶放置感兴趣区（ROIs）来测量相对代谢物浓度和弛豫时间值。采用线性回归分析和Pearson相关性检验对数据进行分析。
结果
衰老导致枕叶灰质、壳核、胼胝体压部和脑桥腹侧的NAA浓度降低，脑桥背侧和壳核的肌酸和磷酸肌酸浓度降低。在选定的脑区中，Cho浓度没有显著变化。随着衰老，小脑白质的T2增加，胼胝体压部的T2降低，而枕叶灰质、手部运动区和壳核的T2'降低，胼胝体压部的T2'增加。在枕叶灰质和壳核中发现NAA浓度与T2'之间存在相关性，在壳核中发现肌酸和磷酸肌酸浓度与T2'之间存在相关性。
结论
正常衰老对脑代谢物和微观结构的影响具有区域依赖性。这两个过程之间的相关性在灰质中很明显。所获得的数据可为未来对患者的研究提供参考。
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