Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, 3-9, Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan; Department of Radiology, Juntendo University School of Medicine, 2-1-1, Hongo, Bunkyo-ku, Tokyo 113-8421, Japan.
Department of Radiology, Juntendo University School of Medicine, 2-1-1, Hongo, Bunkyo-ku, Tokyo 113-8421, Japan.
J Neuroradiol. 2020 Jun;47(4):312-317. doi: 10.1016/j.neurad.2019.04.003. Epub 2019 Apr 26.
The pathophysiology of idiopathic normal pressure hydrocephalus (iNPH) has not been completely clarified. We investigated the brain structure in iNPH using automatic ventricular volumetry, single-tensor diffusion tensor imaging (DTI) and bi-tensor free-water (FW) imaging analyses while focusing on cognitive impairments before and after lumboperitoneal shunt surgery.
This retrospective study included 12 iNPH patients with structural magnetic resonance imaging (MRI) and diffusion MRI (dMRI) on a 3T-MRI scanner who underwent neuropsychological assessments before and after shunting and 8 healthy controls. Ventricular volumetry was conducted on structural MRI datasets using FreeSurfer. Ventricular volume was compared pre- and postoperatively. Correlation analyses were performed between ventricular volume or volume change and neuropsychological scores or score change. Tract-based spatial statistics were performed using dMRI datasets for group analyses between iNPH and controls and between pre- and post-surgery iNPH patients and for correlation analyses using neuropsychological scores. Tract-specific analyses were performed in the anterior thalamic radiation (ATR), followed by comparison and correlation analyses.
The third ventricular volume was significantly decreased after shunting; its volume reduction negatively correlated with a neuropsychological improvement. Compared with controls, iNPH patients had lower fractional anisotropy and higher axial, radial, and mean diffusivities, and FW in the periventricular white matter including ATR, resulting in no difference in FW-corrected indices. Single-tensor DTI indices partially correlated with neuropsychological improvements, while FW-corrected indices had no correlations.
Third ventricle enlargement is possibly linked to cognitive impairment and FW imaging possibly provides better white matter characterization in iNPH.
特发性正常压力脑积水（iNPH）的病理生理学尚未完全阐明。我们通过自动脑室容积测量、单张量扩散张量成像（DTI）和双张量自由水（FW）成像分析研究 iNPH 的脑结构，同时重点关注分流术前和术后的认知障碍。
这项回顾性研究纳入了 12 例在 3T-MRI 扫描仪上进行结构磁共振成像（MRI）和扩散 MRI（dMRI）的 iNPH 患者，这些患者在分流前后接受了神经心理学评估，并纳入了 8 名健康对照者。使用 FreeSurfer 对结构 MRI 数据集进行脑室容积测量。比较术前和术后的脑室容积。对脑室容积或容积变化与神经心理学评分或评分变化之间进行相关性分析。使用 dMRI 数据集进行基于束流的空间统计学分析，比较 iNPH 患者和对照组之间、术前和术后 iNPH 患者之间的组间差异，并进行神经心理学评分的相关性分析。在胼胝体压部进行了束流特异性分析，然后进行了比较和相关性分析。
分流术后第三脑室容积显著减小；其容积减少与神经心理学改善呈负相关。与对照组相比，iNPH 患者的胼胝体压部包括前丘脑辐射（ATR）的各向异性分数较低，轴向、径向和平均扩散率以及 FW 较高，FW 校正指数无差异。单张量 DTI 指数与神经心理学改善部分相关，而 FW 校正指数无相关性。
第三脑室扩张可能与认知障碍有关，FW 成像可能为 iNPH 提供更好的白质特征描述。
