正常中老年人群颅脑表观弥散系数特点分析

目的：探讨40～70岁年龄段正常汉族人颅脑各区域磁共振表观弥散系数（ADC）变化特点，建立正常中老年人群颅脑ADC值变化趋势的基准。方法选择30例无阳性颅脑病征的正常汉族受试者，按年龄段分为3组，使用GE Medical System 3.0 T超导磁共振扫描仪进行头部平扫及弥散加权成像，测量额叶灰质、白质、壳核、丘脑及小脑感兴趣区ADC值，分析各年龄组不同区域脑组织ADC值的关系。结果同一年龄的正常中老年人不同部位的脑组织ADC值不同，其中以额叶灰质最高，其次为壳核、额叶白质与丘脑，小脑最低（均P＜0.05）。不同部位脑组织左右两侧间ADC值均无统计学差异（均P＞0.05）。不同年龄段的正常中老年人额叶灰质、额叶白质、壳核、丘脑与小脑ADC值间均无统计学差异（均P＞0.05）；不同部位脑组织的ADC值随着年龄的增长均呈上升趋势，且40-60岁上升趋势较缓，60岁之后除小脑外，额叶灰质、额叶白质、壳核、丘脑上升趋势加快。结论正常中老年人群同一部位脑组织的ADC值随年龄增长而上升，60岁之后总体上升趋势加快。

Apparent diffusion coefficient measurement of brain tissue in normal middle-aged and aged adults

Objective To investigate the variability and trends of apparent diffusion coefficient （ADC） of different brain segments in normal middle- aged and aged Han adults. Methods Thirty Han normal adult subjects aged 40-70 without positive cerebral symptoms were divided into 3 age groups （40-49, 50-59, 60-70）. Plain scan and diffusion weighted imaging （DWI） were performed by 3.0T MR in al subjects. The images were transferred to ADW 4.3 workstations for post- processing. Regions of interest were placed covering grey and white matter of frontal lobe, putamen, thalamus and cerebel um. The relationship of ADC value with different ages and cerebral regions was analyzed. Results The cerebral tissues of different location had differ-ent values in the same age group. The highest ADC value was detected in gray matter of the frontal lobe, fol owed by putamen, white matter of frontal lobe and the thalamus, and the lowest one was in cerebel um. There was no significant difference in ADCs between two sides of the same cerebral parts of different regions.（P〉0.05）.Although there was no significant difference in ADCs between grey and white matter of frontal lobe, putamen, thalamus and cerebel um of different age groups, the ADC value of the same region tended to increase with age. The changes of ADC value in subjects aged 40-60 presented a much slower rate and an upshift tendency was observed in subjects aged〉60. Conclusion The ADC value of the same region in middle- aged and elderly people tended to increase with the age, particularly in subjects aged〉60 years.