Departments of Radiology, Faculty of Medicine, Bezmialem Vakif University, Istanbul, Turkey.
Departments of Radiology, Faculty of Medicine, Bezmialem Vakif University, Istanbul, Turkey.
Neurochirurgie. 2022 Dec;68(6):595-600. doi: 10.1016/j.neuchi.2022.06.001. Epub 2022 Jun 22.
Chiari type 1 malformation (CMI) is a disorder in which cerebellar tonsils descend below the foramen magnum. Although syringomyelia associated with CMI thought to be caused by hypoplastic posterior fossa and stenosis at the craniocervical junction; it has characteristic neurological and radiological features and the exact mechanism of syringomyelia remains unknown.
The purposes of this study were to gain insight into morphological changes in posterior fossa and to find whether there is a difference in aqueductal stroke volume (ASV) between CMI with syrinx and without syrinx which may be an underlying mechanism of syrinx development.
We consecutively evaluated 85 patients with Chiari malformation between January 2017 and December 2019 who had undergone phase-contrast MRI examination for CSF flow and between 18-60-years-old. We divided patients into two groups as subjects with syrinx (n=19) and without syrinx (n=66). After evaluating morphological changes, peak and average velocity (cm/s), forward and reverse flow volume (μl), net forward flow volume (μl), ASV (aqueductal stroke volume) (μl), aqueductus Sylvi (AS) area (mm), and prepontine cistern diameter to AS diameter ratio (PPC/AS) were calculated. Distribution of variables from two groups was evaluated by using Shapiro-Wilk normality test. Independent t test was used for groups comparison.
The forward and reverse volumes were statistically significantly higher in patients with syrinx (P=0.021, P=0.005 respectively). ASV was significantly increased in patients with syringomyelia (P=0.014). The PPC/AS was significantly lower in patients with syrinx compared to those without (P <0.001). AS area was significantly larger in those with syrinx. (P=0.022). The diameter of foramen magnum was significantly lower in patients with syrinx than those without (P <0.0001). The diameter of the herniated tonsilla at the foramen magnum level was found to be significantly lower in those with syrinx (P=0.011).
Foramen magnum diameter, ASV, diameter of herniated tonsil, and PPC/AS ratio are important factors in syrinx development.
Chiari Ⅰ型畸形（CMI）是一种小脑扁桃体下疝至枕骨大孔以下的疾病。尽管与 CMI 相关的脊髓空洞症被认为是由颅颈交界部的后颅窝发育不良和狭窄引起的，但它具有特征性的神经影像学特征，而脊髓空洞症的确切发病机制尚不清楚。
本研究旨在深入了解后颅窝的形态变化，并探讨小脑扁桃体下疝伴或不伴脊髓空洞症患者的导水管流排量（ASV）是否存在差异，而这可能是脊髓空洞症发展的潜在机制。
我们连续评估了 2017 年 1 月至 2019 年 12 月期间因脑脊液流动而接受相位对比 MRI 检查的 85 例 Chiari 畸形患者，年龄在 18-60 岁之间。我们将患者分为两组，一组为伴有脊髓空洞症（n=19），另一组为不伴有脊髓空洞症（n=66）。在评估形态变化后，计算峰流速和平均流速（cm/s）、正向和反向流量（μl）、净正向流量（μl）、ASV（导水管流排量）（μl）、中脑导水管（AS）面积（mm）和脑桥前池直径与 AS 直径比（PPC/AS）。采用 Shapiro-Wilk 正态性检验评估两组间变量的分布。两组间比较采用独立样本 t 检验。
伴有脊髓空洞症患者的正向和反向流量均显著高于无脊髓空洞症患者（P=0.021，P=0.005）。脊髓空洞症患者的 ASV 明显升高（P=0.014）。伴有脊髓空洞症患者的 PPC/AS 明显低于无脊髓空洞症患者（P <0.001）。伴有脊髓空洞症患者的 AS 面积明显增大（P=0.022）。伴有脊髓空洞症患者的枕骨大孔直径明显小于无脊髓空洞症患者（P <0.0001）。伴有脊髓空洞症患者的寰枕交界部疝出扁桃体直径明显小于无脊髓空洞症患者（P=0.011）。
枕骨大孔直径、ASV、疝出扁桃体直径和 PPC/AS 比值是脊髓空洞症发展的重要因素。
