磁共振NODDI技术在帕金森认知障碍患者海马微观结构的应用

目的  利用神经突方向离散度与密度成像（NODDI）探索帕金森认知障碍（PD-CI）患者海马微观结构的变化，并探讨其与认知功能的关系。方法  选择我院36例帕金森病患者为帕金森病组，选取20例健康志愿者为对照组，对两组进行磁共振检查，检查前对PD患者进行蒙特利尔认知评分（MoCA），其中16例MoCA评分 < 26分为PD-CI组，20例MoCA评分≥26分为帕金森认知正常组。根据NODDI扫描结果获取相关参数：方向离散度指数（ODI）、细胞内体积分数（Vic）和各向同性水分子体积分数（Viso）值，分析感兴趣区ODI、Vic及Viso值的组间差异。将差异有统计学意义的指标分别与MoCA量表评分进行Pearson相关分析，研究各扩散指数与MoCA量表得分的相关性。结果  PD患者海马的ODI值和Vic值均低于健康对照组（P < 0.05），且PD-CI组的ODI值和Vic值低于帕金森认知正常组，差异有统计学意义（P < 0.05），而Viso值与健康对照组相比差异无统计学意义。采用Pearson相关分析对海马ODI值和Vic值与MoCA量表评分进行相关性分析，得出左侧海马ODI值与MoCA量表评分相关性最强（r=0.617，P < 0.05）。结论  NODDI技术能够反映PD患者海马微观结构的改变，并在一定程度上体现了患者的临床认知状态，从而在其辅助诊断中提供重要的参考价值。

Application of magnetic resonance NODDI technique on hippocampal microstructure in patients with Parkinson's cognitive impairment

  Objective  To explore the changes of hippocampal microstructure in patients with Parkinson's disease cognitive impairment (PD-CI) by using neurite orientation dispersion and density imaging (NODDI), and explore its relationship with cognitive function.  Methods  Thirty-six patients with Parkinson's disease in our hospital were selected as Parkinson's disease group, and 20 healthy volunteers were selected as control group. The patients with PD were given Montreal Cognitive Score (MoCA) before examination. Among them, 16 patients with MoCA score < 26 were divided into PD-CI group (PD-CI), and 20 patients with MoCA score ≥26 were divided into normal Parkinson's cognition group. According to the results of NODDI scanning, the related parameters, such as orientation dispersion index (ODI), intracellular volume fraction (Vic) and isotropic water molecule volume fraction (Viso) were obtained, and the differences in ODI, Vic and Viso values in the region of interest were analyzed. The indicators with statistically significant differences were each subjected to Pearson correlation analysis with MoCA scale scores to investigate the correlation between each diffusion index and MoCA scale scores.  Results  The values of ODI and Vic in hippocampus of PD patients were significantly lower than those in healthy control group (P < 0.05), and the values of ODI and Vic in PD-CI group were lower than those in cognitive normal of Parkinson's disease group, with a statistically significant difference (P < 0.05), but there was no significant difference between Viso and healthy control group. The left hippocampal ODI value correlated most strongly with the MoCA scale score (r=0.617, P < 0.05).  Conclusion  NODDI technique can reflect the changes of hippocampal microstructure of PD patients, and to a certain extent, reflecting the clinical cognitive status of PD patients, thus providing important reference value in its auxiliary diagnosis.