ABSTRACT
Objective: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.