摘要目的:采用合成MRI技术评估脑老化过程中大脑白质体积及弛豫值的变化趋势。方法:收集2017年11月至2018年8月在北京医院接受检查的健康成年人107名，根据年龄分为20~39岁组（29名）、40~59岁组（31名）、60~79岁组（30名）、≥80岁组（17名）。所有受检者均接受合成MRI技术扫描，经过后处理获得白质体积、白质体积分数、白质T 1值及白质T 2值。将各参数值与年龄进行非线性回归分析，使用ANOVA检验分析不同年龄组大脑白质及弛豫参数差异。大脑白质体积与白质T 1、T 2值进行Pearson相关分析。 结果:脑白质体积（男、女分别统计）、白质体积分数、白质T 1值及白质T 2值与年龄均呈二次曲线相关趋势［ R 2分别为0.67（男）、0.42（女）、0.44、0.52、0.25， P<0.001］，男性大脑白质体积与年龄有最优拟合度。4个年龄组间男性脑白质体积、女性脑白质体积、白质体积分数、白质T 1值及白质T 2值差异均具有统计学意义（ P<0.05）。男、女大脑白质体积与白质T 1值［ r分别为-0.69（男）、-0.73（女）， P<0.001］及白质T 2值［ r分别为-0.50（男）、-0.49（女）， P<0.001］均呈线性负相关关系。 结论:合成MRI技术可能成为评估大脑老化过程中脑白质体积及弛豫参数改变的有效定量MRI检查方法。

abstractsObjective:To explore the relaxometry and volumetric characteristics of the adults brain at different ages using synthetic MRI.Methods:A total of 107 healthy volunteers in Beijing Hospital from November 2017 to August 2018 were enrolled in this study. According to the age, they were divided into 20-39 years group (29 persons), 40-59 years group (31 persons), 60-79 years group (30 years), and ≥80 years (17 persons). All participants underwent synthetic MRI. Volumetric parameters including white matter volume, white matter fraction, the T 1 and T 2 relaxometry of white matter were obtained. Nonlinear regression analysis was conducted between these parameters and age. ANOVA test was performed to assess the difference of parameters among different age groups. Pearson correlation coefficients between white matter volume and the white matter T 1 and T 2 values were also calculated. Results:White matter volume (male and female separately), white matter fraction, the T 1 and T 2 relaxometry of white matter followed a second order polynomial relationship with age [ R2 =0.67(male), 0.42(female), 0.44, 0.52, 0.25, P<0.001] and the white matter volume of males had the best goodness of fit. Significant differences were observed in white matter volume (male and female separately), white matter fraction, T 1 and T 2 relaxometry of the white matter among four age groups ( P<0.05). The white matter volume of male and female negatively linearly correlated with the T 1 [ r =-0.69(male), -0.73(female), P<0.001)] and T 2 [ r=-0.50(male), -0.49(female), P<0.001] of white matter. Conclusion:Synthetic MRI has demonstrated potential in detecting white matter alterations of relaxometry and volumetry during the aging process.