正常人脑白质ADC值与年龄的相关性研究

目的探讨不同年龄组正常人脑白质的ADC值的特点及规律，建立正常人脑不同部位白质的标准ADC值，为弥散的临床应用及研究提供客观依据。方法收集60名正常健康体检者，对所有研究对象行头颅常规MR检查及平面回波弥散加权成像检查，获得各相同性弥散加权图。每个研究对象选16个感兴趣区，通过公式ADC=ln（S低／S高）／（b高-b低）计算每个感兴趣区的平均ADC值。结果正常人脑白质总的平均ADCave值为0．76±0．03（0．65～0．83）×10^-3mm^2／s，白质的平均ADC值随着年龄增长而增加，与年龄呈正相关，相关系数为0．46。结论不同年龄组正常人脑白质的ADC值有一定的变化规律，在临床对疾病的诊断时要考虑到该变化，以免误诊和漏诊；弥散定量测量在一定程度上可以用来评价正常人脑随着年龄增长伴随微观水平的改变，弥散技术有可能在脑老化研究中起到举足轻重的作用。

The Research on Correlation between ADC Values to Age of White Matter of Normal Brain

Purpose To investigate the characteristics and regularity of white matter of different age groups, to establish the standard ADC values of different regions of normal brain and to provide the objective evidences for the clinical application and study.Methods Sixty healthy people＇s MR imagings were reviewed.All of them underwent routine MRI scans and EPI DWI,and isotropic diffusion weighted images were obtained.Sixteen ROIs were selected for each object, and ADC values were calculated by the formula： ADC=ln（Slow/Shigh）/（bhigh-blow）.Results The mean ADC value in total white matter is 0.76 ± 0.03（0.65-0.83） × 10^3mm^2/s,the white matter＇ADC values increase with age.There was positive correlation with age.The correlation coefficient is 0.46.Conclusions There are some regularities in the ADC values in brain of healty people of different age groups.And these changes must be paid attention to,to avoid misdiagnosis and missed diagnosis.To some degree,the quantitative measurement of diffusion can be used to evaluate the ultrastructure changes with age in brain of healthy people.The diffusion technique may play an important part in research on brain aging.