Raininko Raili, Mattsson Peter
Departments of Radiology, Uppsala University, Uppsala, Sweden.
Acta Radiol. 2010 Apr;51(3):309-15. doi: 10.3109/02841850903476564.
Age- and sex-related changes of metabolites in healthy adult brains have been examined with different (1)H magnetic resonance spectroscopy (MRS) methods in varying populations, and with differing results. A long repetition time and short echo time technique reduces quantification errors due to T(1) and T(2) relaxation effects and makes it possible to measure metabolites with short T(2) relaxation times.
To examine the effect of age on the metabolite concentrations measured by (1)H MRS in normal supraventricular white matter using a long repetition time (TR) and a short echo time (TE).
Supraventricular white matter of 57 healthy subjects (25 women, 32 men), aged 13 to 72 years, was examined with a single-voxel MRS at 1.5T using a TR of 6000 ms and a TE of 22 ms. Tissue water was used as a reference in quantification.
Myoinositol increased slightly and total N-acetyl aspartate (NAA) decreased slightly with increasing age. Glutamine/glutamate complex (Glx) showed U-shaped age dependence, with highest concentrations in the youngest and oldest subjects. No significant age dependence was found in total choline and total creatine. No gender differences were found. Macromolecule/ lipid (ML) fractions were reliably measurable only in 36/57 or even fewer subjects and showed very large deviations.
The concentrations of several metabolites in cerebral supraventricular white matter are age dependent on (1)H MRS, even in young and middle-aged people, and age dependency can be nonlinear. Each (1)H MRS study of the brain should therefore take age into account, whereas sex does not appear to be so important. The use of macromolecule and lipid evaluations is compromised by less successful quantification and large variations in healthy people.
不同人群采用不同的氢磁共振波谱（MRS）方法对健康成人大脑代谢物的年龄和性别相关变化进行了研究，结果各异。长重复时间和短回波时间技术可减少因T(1)和T(2)弛豫效应导致的定量误差，并能够测量具有短T(2)弛豫时间的代谢物。
采用长重复时间（TR）和短回波时间（TE），研究年龄对正常室上白质中氢MRS测量的代谢物浓度的影响。
对57名年龄在13至72岁之间的健康受试者（25名女性，32名男性）的室上白质进行了1.5T的单体素MRS检查，采用6000ms的TR和22ms的TE。在定量分析中，以组织水作为参考。
随着年龄增长，肌醇略有增加，总N-乙酰天门冬氨酸（NAA）略有下降。谷氨酰胺/谷氨酸复合物（Glx）呈现U型年龄依赖性，在最年轻和最年长的受试者中浓度最高。总胆碱和总肌酸未发现明显的年龄依赖性。未发现性别差异。大分子/脂质（ML）分数仅在36/57名受试者中甚至更少的受试者中可可靠测量，且显示出非常大的偏差。
即使在年轻人和中年人中，大脑室上白质中几种代谢物的浓度在氢MRS上也存在年龄依赖性，且年龄依赖性可能是非线性的。因此，每项大脑氢MRS研究都应考虑年龄因素，而性别似乎不那么重要。在健康人群中，大分子和脂质评估的定量不太成功且变化较大，这影响了其应用。
