DTI纤维追踪法定量分析90名正常国人脑白质老化

目的 采用DTI纤维追踪法定量比较不同年龄组正常自愿者椎体束从大脑脚到中央前回部分(PRPT)FA值的差别及其意义.方法 将90名正常志愿者按年龄分为6组,进行基于纤维追踪的定量DTI研究,图像标准化后分析各组PRPT的FA值与年龄组老化的关系.结果 各年龄组双侧PRPT的FA值分布相似,最低点在放射冠处,最高峰为内囊后肢;各段FA值随年龄增长呈下降趋势,表明这些部位的纤维随年龄增长发生了老化,其中以额叶老化最为明显;并发现额叶及大脑脚白质老化过程中存在突然变化.结论 DTI可以作为评价脑组织细微结构变化和老化过程的敏感工具;额叶及大脑脚白质老化过程中存在突变是否为脑生理上老化的标志有待进一步研究.

White matter fiber tracking method for the study of aging-quantitative diffusion tensor imaging analysis of ninety healthy adult Chinese

Objective To investigate the difference and significance of fractional anisotropy (FA) of precentral portion of the pyramidal tract (PRPT, from cerebral peduncle to precentral gyrus) in different age-groups healthy volunteers using quantitative diffusion tensor imaging (DTI) based on fiber tractography. Methods Quantitative DTI based on fiber tractography was performed in 90 healthy volunteers (20-83 years, divided into 6 age groups) at a 1.5T MR scanner. Standardized images data was analyzed for the relationship between FA values of PRPT and aging. Results The FA value of bilateral PRPT in each age group distributed similarly, in which FA value of corona radiata was the lowest and the posterior limb of the internal capsule was the highest. The FA values of sections were declining with aging, the fibers of these parts had significantly aging, and the most obvious aging part was the frontal lobe. The procedure of aging in the frontal lobe and cerebral peduncle existed mutation period. Conclusion DTI is a sensitive method for detecting the microstructural changes and aging process of brain white matter. Whether the mutation of aging in the frontal lobe and cerebral peduncle is the physical signs of aging should be further examined.