Reiss-Zimmermann Martin, Scheel Michael, Dengl Markus, Preuß Matthias, Fritzsch Dominik, Hoffmann Karl-Titus
Department of Neuroradiology, University of Leipzig, Liebigstr. 20, 04103 Leipzig, Germany
Department of Neuroradiology, Charité Berlin, Charitéplatz 1, 10117 Berlin, Germany.
Acta Radiol. 2014 Jun;55(5):622-30. doi: 10.1177/0284185113502334. Epub 2013 Aug 31.
Normal pressure hydrocephalus (NPH) has been an ongoing and challenging field of research for the past decades because two main issues are still not fully understood: the pathophysiologic mechanisms underlying ventricular enlargement and prediction of outcome after surgery.
To evaluate changes in diffusion tensor imaging (DTI) derived parameters in patients with suspected normal pressure hydrocephalus before and after withdrawal of cerebrospinal fluid (CSF).
Twenty-four consecutive patients with clinical and radiological suspicion of NPH and 14 age-matched control subjects were examined with DTI on a clinical 3T scanner. Patients were examined before and 6-36 h after CSF drainage (interval between scans, 5 days). Fifteen patients were finally included in data analysis. Fractional anisotropy (FA) and mean, parallel, and radial diffusivity (MD, PD, RD) were evaluated using a combination of a ROI-based approach and a whole-brain voxel-by-voxel analysis.
Alteration of DTI parameters in patients with suspected NPH is regionally different. Compared to the control group, we found an elevation of FA in the subcortical white matter (SCWM) and corpus callosum, whereas the other diffusion parameters showed an increase throughout the brain in variable extent. We also found a slight normalization of RD in the SCWM in patients after lumbar drainage.
Our results show that DWI parameters are regionally dependent and reflect multifactorial (patho-) physiological mechanisms, which need to be interpreted carefully. It seems that improvement of gait is caused by a decrease of interstitial water deposition in the SCWM.
在过去几十年里，正常压力脑积水（NPH）一直是一个持续且具有挑战性的研究领域，因为两个主要问题仍未完全理解：脑室扩大的病理生理机制以及手术后预后的预测。
评估疑似正常压力脑积水患者在脑脊液（CSF）引流前后扩散张量成像（DTI）衍生参数的变化。
连续24例临床和影像学怀疑为NPH的患者以及14例年龄匹配的对照受试者在临床3T扫描仪上进行DTI检查。患者在脑脊液引流前和引流后6 - 36小时进行检查（扫描间隔为5天）。最终15例患者纳入数据分析。使用基于感兴趣区域（ROI）的方法和全脑逐体素分析相结合的方式评估分数各向异性（FA）以及平均、平行和径向扩散率（MD、PD、RD）。
疑似NPH患者的DTI参数改变存在区域差异。与对照组相比，我们发现皮质下白质（SCWM）和胼胝体中的FA升高，而其他扩散参数在全脑均有不同程度的增加。我们还发现腰椎引流后患者SCWM中的RD略有恢复正常。
我们的结果表明，DWI参数具有区域依赖性，反映了多因素（病理 - ）生理机制，需要仔细解读。步态改善似乎是由SCWM中间质水沉积减少所致。
