BackgroundCommunicating hydrocephalus is a disease where the cerebral ventricles are enlarged. It is characterized by the absence of detectable cerebrospinal fluid (CSF) outflow obstructions and often with increased CSF pulsatility measured in the cerebral aqueduct (CA). We hypothesize that the cardiac-related pulsatile flow over the CA, with fast systolic outflow and slow diastolic inflow, can generate net pressure effects that could source the ventriculomegaly in these patients. This would require a non-zero cardiac cycle averaged net pressure difference (ΔPnet) over the CA, with higher average pressure in the lateral and third ventricles.MethodsWe tested the hypothesis by calculating ΔPnet across the CA using computational fluid dynamics based on prospectively collected high-resolution structural (FIESTA-C, resolution 0.39 × 0.39 × 0.3 mm3) and velocimetric (2D-PCMRI, in-plane resolution 0.35 × 0.35 mm2) MRI-data from 30 patients investigated for communicating hydrocephalus.ResultsThe ΔPnet due to CSF pulsations was non-zero for the study group (p = 0.03) with a magnitude of 0.2 ± 0.4 Pa (0.001 ± 0.003 mmHg), with higher pressure in the third ventricle. The maximum pressure difference over the cardiac cycle ΔPmax was 20.3 ± 11.8 Pa and occurred during systole. A generalized linear model verified an association between ΔPnet and CA cross-sectional area (p = 0.01) and flow asymmetry, described by the ratio of maximum inflow/outflow (p = 0.04), but not for aqueductal stroke volume (p = 0.35).ConclusionsThe results supported the hypothesis with respect to the direction of ΔPnet, although the magnitude was low. Thus, although the pulsations may generate a pressure difference across the CA it is likely too small to explain the ventriculomegaly in communicating hydrocephalus.

中文翻译：

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脑导水管的搏动性脑脊液流动会导致脑室扩大吗？交通性脑积水患者的前瞻性研究

背景交通性脑积水是一种脑室扩大的疾病。它的特点是没有可检测到的脑脊液 (CSF) 流出阻塞，并且通常在脑导水管 (CA) 中测量到 CSF 搏动增加。我们假设通过 CA 的心脏相关脉动流，具有快速收缩流出和缓慢舒张流入，可以产生净压力效应，可能导致这些患者的心室扩大。这将需要 CA 上的非零心动周期平均净压差 (ΔPnet)，侧脑室和第三脑室的平均压力更高。 - 分辨率结构（FIESTA-C，分辨率 0.39 × 0.39 × 0. 3 mm3) 和测速 (2D-PCMRI, 平面分辨率 0.35 × 0.35 mm2) 来自 30 名因交通性脑积水而接受调查的患者的 MRI 数据。幅度为 0.2 ± 0.4 Pa (0.001 ± 0.003 mmHg)，第三脑室压力较高。心动周期内的最大压力差 ΔPmax 为 20.3 ± 11.8 Pa，发生在收缩期。广义线性模型验证了 ΔPnet 和 CA 横截面积 (p = 0.01) 与流量不对称之间的关联，由最大流入/流出比 (p = 0.04) 描述，但不适用于导水管每搏输出量 (p = 0.35) .结论结果支持关于 ΔPnet 方向的假设，尽管幅度很小。因此，