扩散峰度成像在轻度认知功能障碍患者额叶前皮质微结构变化中的应用分析

Application analysis of diffusion kurtosis imaging in microstructural changes of prefrontal cortex in patients with mild cognitive impairment

目的探讨MR扩散峰度成像(DKI)技术在轻度认知功能障碍(MCI)患者额叶前皮质微结构变化的应用价值。方法回顾性连续纳入2018年1月至12月于首都医科大学附属北京朝阳医院神经内科脑小血管病住院患者79例,经头部MRI和MR血管成像证实,并采用蒙特利尔认知评估(MoCA)量表对总体认知功能进行评估。根据是否存在MCI,将79例患者分为MCI组(46例)和无MCI组(33例)。记录并分析两组患者一般临床资料;神经心理学测评结果,包括MoCA量表、汉密尔顿抑郁量表(HAMD)、汉密尔顿焦虑量表(HAMA);常规MR形态学及DKI扫描结果。选择患者额叶前皮质为感兴趣区,即双侧背外侧额上回、内侧额上回、前扣带和旁扣带脑回;测量兴趣区的DKI相关参数,包括平均扩散率(MD)、扩散各向异性分数(FA)、轴向扩散峰度(AK)、平均扩散峰度(MK)和径向扩散峰度(RK)。对多个兴趣区的多次比较应用Bonferroni方法校正P值,校正P值以P <0. 008为差异有统计学意义。结果 (1) MCI组患者MoCA量表评分低于无MCI组,组间差异有统计学意义[20(19,22)分比27(25,28)分,Z=-6. 836,P <0. 01];年龄、性别、受教育年限、HAMD评分、HAMA评分的组间差异均无统计学意义(均P> 0. 05)。(2)在右侧前扣带和旁扣带脑回,MCI组患者FA、AK、MK值均低于无MCI组,组间差异均有统计学意义(0. 16±0. 03比0. 18±0. 03、0. 64±0. 08比0. 70±0. 06、0. 67±0. 09比0. 73±0. 06,均P <0. 008),MD、RK值的组间差异均无统计学意义(均P> 0. 008);在左侧前扣带和旁扣带脑回,MD、FA、AK、MK、RK值的组间差异均无统计学意义(均P> 0. 008)。(3) MD、FA、AK、MK及RK值在双侧背外侧额上回、双侧内侧额上回的组间差异均无统计学意义(均P> 0. 008)。结论 DKI技术可尝试用于MCI患者额叶前皮质微结构改变的观察,DKI相关参数在MCI患者临床影像学评估中具有一定的价值。

Objective To investigate the application value of diffusion kurtosis imaging(DKI)in the changes of prefrontal cortex microstructures in patients with mild cognitive impairment(MCI).Methods A total of 79 consecutive patients with cerebral small vascular disease admitted to the Department of Neurology,Chaoyang Hospital,Capital Medical University between January 2018 and December 2018 were enrolled retrospectively.They were confirmed by head MRI and MR angiography and Montreal cognitive assessment scale(MoCA)was used to assess the overall cognitive function.According to the presence or absence of MCI,79 patients were divided into MCI group(n=46)and non-MCI group(n=33).The general clinical data of the two groups of patients were recorded and analyzed;neuropsychological assessment results,including MoCA scale,Hamilton depression rating scale(HAMD),Hamilton anxiety rating scale(HAMA);conventional MR morphology,and DKI scan results.The prefrontal cortex of the patients was selected as the region of interest,i.e.,bilateral dorsolateral superior gyrus,medial superior frontal gyrus,anterior cingulate,and paracingulate gyrus;the DKI related parameters of the region of interest were measured,including mean diffusivity(MD),fractional anisotropy(FA),axial kurtosis(AK),mean kurtosis(MK),and radial kurtosis(RK).The Bonferroni method was used to adjust P values for multiple comparisons of multiple regions of interest.The P value was adjusted with P<0.008(0.05/6=0.0083)as the difference was statistically significant.Results(1)The MoCA scale score in the MCI group was lower than that in the non-MCI group.There was significant difference between the two groups(20[19,22]vs.27[25,28],Z=-6.836,P<0.01).There were no significant differences in age,gender,years of education,HAMD score,and HAMA score between the two groups(all P>0.05).(2)In the right anterior cingulate and paracingulate gyrus,the FA,AK and MK values of the MCI group were lower than those of the non-MCI group.The differences were statistically significant between groups(0.16±0.03 vs.0.18±0.03,0.64±0.08 vs.0.70±0.06,and 0.67±0.09 vs.0.73±0.06,all P<0.008).There were no significant differences in MD and RK values between the two groups(all P>0.008).In the left anterior cingulate and paracingulate gyrus,there were no significant differences in MD,FA,AK,MK and RK between the two groups(all P>0.008).(3)There were no significant differences in the MD,FA,AK,MK and RK values between the bilateral dorsolateral superior frontal gyrus and bilateral medial superior frontal gyrus(all P>0.008).Conclusions DKI technique can be used to observe the microstructural change of prefrontal cortex matter in patients with MCI.The parameters related to DKI have certain value in clinical imaging evaluation of patients with MCI.