Department of Neurosurgery, Nagoya City University Graduate School of Medical Science, 1 Kawasumi, Mizuho-Cho, Mizuho-Ku, Nagoya, Aichi, 467-8601, Japan.
Department of Neurosurgery, Shiga University of Medical Science, Shiga, Japan.
Fluids Barriers CNS. 2023 Mar 10;20(1):16. doi: 10.1186/s12987-023-00415-6.
In the cerebrospinal fluid (CSF) dynamics, the pulsations of cerebral arteries and brain is considered the main driving force for the reciprocating bidirectional CSF movements. However, measuring these complex CSF movements on conventional flow-related MRI methods is difficult. We tried to visualize and quantify the CSF motion by using intravoxel incoherent motion (IVIM) MRI with low multi-b diffusion-weighted imaging.
Diffusion-weighted sequence with six b values (0, 50, 100, 250, 500, and 1000 s/mm) was performed on 132 healthy volunteers aged ≥ 20 years and 36 patients with idiopathic normal pressure hydrocephalus (iNPH). The healthy volunteers were divided into three age groups (< 40, 40 to < 60, and ≥ 60 years). In the IVIM analysis, the bi-exponential IVIM fitting method using the Levenberg-Marquardt algorithm was adapted. The average, maximum, and minimum values of ADC, D, D*, and fraction of incoherent perfusion (f) calculated by IVIM were quantitatively measured in 45 regions of interests in the whole ventricles and subarachnoid spaces.
Compared with healthy controls aged ≥ 60 years, the iNPH group had significantly lower mean f values in all the parts of the lateral and 3rd ventricles, whereas significantly higher mean f value in the bilateral foramina of Luschka. In the bilateral Sylvian fossa, which contain the middle cerebral bifurcation, the mean f values increased gradually with increasing age, whereas those were significantly lower in the iNPH group. In the 45 regions of interests, the f values in the bilateral foramina of Luschka were the most positively correlated with the ventricular size and indices specific to iNPH, whereas that in the anterior part of the 3rd ventricle was the most negatively correlated with the ventricular size and indices specific to iNPH. Other parameters of ADC, D, and D* were not significantly different between the two groups in any locations.
The f value on IVIM MRI is useful for evaluating small pulsatile complex motion of CSF throughout the intracranial CSF spaces. Patients with iNPH had significantly lower mean f values in the whole lateral ventricles and 3rd ventricles and significantly higher mean f value in the bilateral foramina of Luschka, compared with healthy controls aged ≥ 60 years.
在脑脊液（CSF）动力学中，大脑动脉的搏动和大脑被认为是 CSF 往复双向运动的主要驱动力。然而，使用传统的与流动相关的 MRI 方法测量这些复杂的 CSF 运动是很困难的。我们试图通过使用低多 b 值扩散加权成像的体素内不相干运动（IVIM）MRI 来可视化和量化 CSF 运动。
对 132 名年龄≥20 岁的健康志愿者和 36 名特发性正常压力脑积水（iNPH）患者进行了六个 b 值（0、50、100、250、500 和 1000 s/mm）的扩散加权序列。健康志愿者分为三组（<40 岁、40 至<60 岁和≥60 岁）。在 IVIM 分析中，采用 Levenberg-Marquardt 算法的双指数 IVIM 拟合方法。通过 IVIM 定量测量了整个脑室和蛛网膜下腔 45 个感兴趣区域的 ADC、D、D*和非相干灌注分数（f）的平均值、最大值和最小值。
与年龄≥60 岁的健康对照组相比，iNPH 组所有侧脑室和第三脑室部分的平均 f 值明显较低，而双侧 Luschka 孔的平均 f 值明显较高。在包含大脑中动脉分叉的双侧大脑外侧裂，f 值随年龄的增加而逐渐增加，而 iNPH 组的 f 值明显较低。在 45 个感兴趣区域中，双侧 Luschka 孔的 f 值与脑室大小和 iNPH 特异性指数最正相关，而第三脑室前部的 f 值与脑室大小和 iNPH 特异性指数最负相关。在任何部位，ADC、D 和 D*的其他参数在两组之间均无显著差异。
IVIM MRI 上的 f 值可用于评估颅内 CSF 空间内 CSF 小而复杂的脉动运动。与年龄≥60 岁的健康对照组相比，iNPH 患者整个侧脑室和第三脑室的平均 f 值明显较低，双侧 Luschka 孔的平均 f 值明显较高。
