Supplementary Material for: Utility of True Fast Imaging with Steady-State Precession in Detecting Arachnoid Veils of the Posterior Fossa

<b><i>Introduction:</i></b> Arachnoid membranes are well recognized as a cause of cerebrospinal fluid (CSF) flow impairment in disorders such as obstructive hydrocephalus and syringohydromyelia, but can be difficult to detect with standard noninvasive imaging techniques. True fast imaging with steady-state precession (TrueFISP) can exhibit brain pulsations and CSF dynamics with high spatiotemporal resolution. Here, we demonstrate the utility of this technique in the diagnosis and management of arachnoid membranes in the posterior fossa. <b><i>Case Presentations:</i></b> Three symptomatic children underwent cine TrueFISP imaging for suspicion of CSF membranous obstruction. Whereas standard imaging failed to or did not clearly visualize the site of an obstructive lesion, preoperative TrueFISP identified a membrane in all 3 cases. The membranes were confirmed intraoperatively, and postoperative TrueFISP helped verify adequate marsupialization and recommunication of CSF flow. Two out of the 3 cases showed a decrease in cerebellar tonsillar pulsatility following surgery. All children showed symptomatic improvement. <b><i>Conclusion:</i></b> TrueFISP is able to detect pulsatile arachnoid membranes responsible for CSF outflow obstruction that are otherwise difficult to visualize using standard imaging techniques. We advocate use of this technology in pre- and postsurgical decision-making as it provides a more representative image of posterior fossa pathology and contributes to our understanding of CSF flow dynamics. There is potential to use this technology to establish prognostic biomarkers for disorders of CSF hydrodynamics.

**引言：**
蛛网膜隔膜已被广泛公认为梗阻性脑积水、脊髓空洞积水症等疾病中脑脊液（cerebrospinal fluid, CSF）循环障碍的诱因之一，但通过标准无创成像技术往往难以检出。稳态自由进动快速成像（TrueFISP）可凭借较高的时空分辨率，清晰显示脑搏动与脑脊液动力学特征。本研究旨在探讨该技术在后颅窝蛛网膜隔膜的诊断与诊疗中的应用价值。

**病例介绍：**
3例出现临床症状的儿童因怀疑存在脑脊液膜性梗阻，接受了电影稳态自由进动快速成像（cine TrueFISP）检查。尽管标准成像未能或无法清晰显示梗阻性病变的位置，但术前TrueFISP在全部3例病例中均成功检出了隔膜。术中均证实了该隔膜的存在，术后TrueFISP可验证脑脊液循环已通过充分的囊壁开窗造口术实现再通。3例中的2例在术后可见小脑扁桃体搏动幅度降低，所有患儿的临床症状均得到改善。

**结论：**
TrueFISP可检出导致脑脊液流出梗阻的搏动性蛛网膜隔膜，而这类隔膜通过标准成像技术往往难以可视化。我们建议在术前与术后诊疗决策中采用该技术，因其可更真实地反映后颅窝病变情况，并有助于加深我们对脑脊液循环动力学的理解。该技术还有望用于构建脑脊液循环动力障碍相关疾病的预后生物标志物。