高场强DTI技术在脑组织正常老化研究中的运用

Application of high-field-strength diffusion tensor imaging on normal aging brain tissue

目的利用高场强磁共振设备,通过比较青年和中老年的脑弥散张量成像(DTI)的平均弥散系数(ADC)及各向异性(FA)值,探讨DTI技术在脑组织正常老化研究中的运用。方法随机选取西南大学脑成像中心2011年9月-2012年1月行MRI实验的健康志愿者60例作为研究对象,根据年龄分为青年组(20~30岁)与中老年组(40~59岁),每组30例。对研究对象行DTI,分析得出其不同感兴趣区域(ROI)的ADC及FA值。结果不同性别研究对象相同ROI的ADC值差异均无统计学意义(P>0.05),不同性别研究对象相同ROI的FA值差异亦均无统计学意义(P>0.05)。不同年龄段男性研究对象的ADC值比较,除左侧丘脑、双侧脑脊液及双侧枕叶皮质外,其他ROI的ADC值差异均有统计学意义(P<0.05);不同年龄段女性研究对象的ADC值比较,除右侧丘脑、双侧脑脊液及双侧枕叶皮质外,其他ROI的ADC值差异均有统计学意义(P<0.05)。不同年龄段男性研究对象的FA值比较,除右侧丘脑、双侧脑脊液及双侧枕叶皮质外,其他ROI的FA值差异均有统计学意义(P<0.05);不同年龄段女性研究对象的FA值比较,除双侧丘脑、双侧脑脊液及双侧枕叶皮质外,其他ROI的FA值差异均有统计学意义(P<0.05)。结论DTI是一种具有无创性且可显示脑白质纤维束结构异常的敏感工具,它可以通过脑组织FA及ADC值的改变而反映脑组织细微结构的改变。这不仅有利于脑细胞正常老化的前期的研究,也对因为正常老化而产生的老年性颅脑疾病的预防及早期发现具有重要意义。

Objective To investigate the application of diffusion tensor imaging(DTI)on normal aging brain tissue by comparing average diffusion coefficient(ADC)and fraction anisotropy(FA)of the young and middle-elder people via high field magnetic resonance equipment.Methods Sixty healthy volunteers who underwent Magnetic Resonance Imaging(MRI)in brain imaging center of Southwest University from September 2011 to January 2012 were selected as study objects and were equally divided into the young group(20-30 years old)and the middle-elder group(40-59 years old).All study objects experienced DTI and ADC and FA value of different area of interest(ROI)were gained.Results ADC values of study objects with different gender but same ROI had no statistically significant differences(P>0.05),and FA values of study objects with different gender but same ROI had no statistically significant differences(P>0.05).Comparison of ADC values in male of different age groups showed that ADC values of other ROI had statistically significant differences(P<0.05),but except left thalamus,bilateral cerebrospinal fluid and bilateral occipital cortex.Comparison of ADC values in female of different age groups showed that ADC values of other ROI had statistically significant differences(P<0.05),but except right thalamus,bilateral cerebrospinal fluid and bilateral occipital cortex.Comparison of FA values in male of different age groups showed that FA values of other ROI had statistically significant differences(P<0.05),but except right thalamus,bilateral cerebrospinal fluid and bilateral occipital cortex.Comparison of FA values in female of different age groups showed that FA values of other ROI had statistically significant differences(P<0.05),but except bilateral thalamus,bilateral cerebrospinal fluid and bilateral occipital cortex.Conclusion DTI is a sensitive equipment which is noninvasive and can demonstrate the abnormal white matter fiber tracts,reflecting the change of brain minute structure according to changes of FA and ADC value.Therefore,it is beneficial to study the normal pre-aging and has significance to prevent and early diagnose the geratic cerebral diseases caused by normal aging.