基于DKI技术的MK参数值评价中重度OSA患者脑微结构损伤及认知功能障碍的初步研究

Preliminary study of MK parametric map based on DKI technique in evaluating brain microstructural damage and cognitive impairment in patients with moderate and severe OSA

目的利用磁共振扩散峰度成像(diffusion kurtosis imaging,DKI)技术的平均扩散峰度(mean kurtosis,MK)值探讨成人中、重度阻塞性睡眠呼吸暂停(obstructive sleep apnea,OSA)患者脑组织微结构完整性的变化及其与神经认知功能障碍的关系,进而探究OSA患者认知改变的潜在神经病理机制。材料与方法收集中、重度OSA患者40例(OSA患者组)及健康对照者40例(对照组),两组之间年龄、性别、受教育年限相匹配,并进行认知功能评估及MRI检查。通过后处理程序对MK参数图上的全脑各灰、白质脑区进行定量值提取。将两组研究对象之间各脑区的MK值进行比较,并采用偏相关分析方法对OSA患者组有差异脑区的MK值与呼吸睡眠参数及认知评分进行相关性分析。结果与对照组相比,OSA患者组20个脑区的MK值减低,包括双侧中央前、后回皮质、左侧扣带回、海马等脑区,差异有统计学意义(P<0.05,FDR校正)。OSA患者组蒙特利尔认知评估量表(Montreal Cognitive Assessment,MoCA)总分、视空间与执行功能、抽象、延迟回忆评分均明显减低,差异有统计学意义(P<0.05)。偏相关分析结果显示,OSA患者组的最低血氧饱和度(lowest oxygen saturation,LSaO2)与右侧中央前回、后回皮质、双侧顶叶皮质的MK值呈正相关(r=0.446、0.350、0.456、0.442,P<0.05),延迟回忆评分与左侧海马的MK值呈正相关(r=0.353,P<0.05)。结论DKI可敏感地发现中、重度OSA患者的脑组织微结构损伤,且部分脑区微结构的异常改变与认知功能障碍存在一定的相关性,为探索OSA患者认知障碍的神经病理机制提供了影像学依据。

and delayed recall in the OSA group were significantly lower,the difference was statistically significant(P<0.05).The results of partial correlation analysis showed that the lowest oxygen saturation(LSaO2)was positively correlated with the MK of the right precentral gyrus,postcentral gyrus and bilateral parietal cortex(r=0.446,0.350,0.456,0.442,P<0.05)in OSA group.The delayed recall score was positively correlated with the MK of the left hippocampus(r=0.353,P<0.05).Conclusions:DKI imaging can sensitively detect the microstructural damage of brain tissue in patients with moderate and severe OSA,and the abnormal microstructural changes in some brain regions are related to cognitive dysfunction,which provides imaging basis for exploring the neuropathological mechanism of cognitive impairment in patients with OSA.