1Department of Radiology, Phoenix Children's Hospital, Phoenix, Arizona.
Departments of2Neurosurgery.
J Neurosurg Pediatr. 2024 Aug 23;34(5):423-431. doi: 10.3171/2024.6.PEDS24117. Print 2024 Nov 1.
Hydrocephalus is a challenging neurosurgical condition due to nonspecific symptoms and complex brain-fluid pressure dynamics. Typically, the assessment of hydrocephalus in children requires radiographic or invasive pressure monitoring. There is usually a qualitative focus on the ventricular spaces even though stress and shear forces extend across the brain. Here, the authors present an MRI-based vector approach for voxelwise brain and ventricular deformation visualization and analysis.
Twenty pediatric patients (mean age 7.7 years, range 6 months-18 years; 14 males) with acute, newly diagnosed hydrocephalus requiring surgical intervention for symptomatic relief were randomly identified after retrospective chart review. Selection criteria included acquisition of both pre- and posttherapy paired 3D T1-weighted volumetric MRI (3D T1-MRI) performed on 3T MRI systems. Both pre- and posttherapy 3D T1-MRI pairs were aligned using image registration, and subsequently, voxelwise nonlinear transformations were performed to derive two exemplary visualizations of compliance: 1) a whole-brain vector map projecting the resulting deformation field on baseline axial imaging; and 2) a 3D heat map projecting the volumetric changes along ventricular boundaries and the brain periphery.
The patients underwent the following interventions for treatment of hydrocephalus: endoscopic third ventriculostomy (n = 6); external ventricular drain placement and/or tumor resection (n = 10); or ventriculoperitoneal shunt placement (n = 4). The mean time between pre- and postoperative imaging was 36.5 days. Following intervention, the ventricular volumes decreased significantly (mean pre- and posttherapy volumes of 151.9 cm3 and 82.0 cm3, respectively; p < 0.001, paired t-test). The largest degree of deformation vector changes occurred along the lateral ventricular spaces, relative to the genu and splenium. There was a significant correlation between change in deformation vector magnitudes within the cortical layer and age (p = 0.011, Pearson), as well as between the ventricle size and age (p = 0.014, Pearson), suggesting higher compliance among infants and younger children.
This study highlights an approach for deformation analysis and vector mapping that may serve as a topographic visualizer for therapeutic interventions in patients with hydrocephalus. A future study that correlates the degree of cerebroventricular deformation or compliance with intracranial pressures could clarify the potential role of this technique in noninvasive pressure monitoring or in cases of noncompliant ventricles.
脑积水是一种具有挑战性的神经外科疾病，其症状不具有特异性，且脑内液体压力动态较为复杂。通常，儿童脑积水的评估需要进行放射性或有创性压力监测。尽管压力和剪切力会延伸到整个大脑，但评估时通常会侧重于脑室空间。本文作者提出了一种基于 MRI 的体素变形可视化和分析的向量方法。
回顾性分析病历后，随机选择 20 名患有急性、新诊断脑积水的儿科患者（平均年龄 7.7 岁，范围 6 个月-18 岁；14 名男性），这些患者均需要手术干预以缓解症状。入选标准包括在 3T MRI 系统上采集治疗前后配对的 3D T1 加权容积 MRI（3D T1-MRI）。使用图像配准对治疗前后的 3D T1-MRI 对进行配准，然后进行体素非线性变换，以得出两种顺应性的示例可视化结果：1）一个整体大脑向量图，将所得变形场投影到基线轴位成像上；2）一个 3D 热图，将体积变化沿脑室边界和脑外周投影。
患者接受了以下干预措施来治疗脑积水：内镜第三脑室造瘘术（n=6）；外部脑室引流管放置和/或肿瘤切除术（n=10）；或脑室-腹腔分流术（n=4）。治疗前后成像的平均时间为 36.5 天。干预后，脑室体积明显减小（分别为治疗前后的平均体积 151.9cm3 和 82.0cm3，p＜0.001，配对 t 检验）。变形向量变化最大的程度发生在侧脑室空间，相对于膝状体和穹窿。皮质层内变形向量幅度的变化与年龄之间存在显著相关性（p=0.011，Pearson），以及脑室大小与年龄之间存在显著相关性（p=0.014，Pearson），提示婴儿和幼儿的顺应性更高。
本研究强调了一种变形分析和向量映射的方法，可作为脑积水患者治疗干预的地形可视化方法。未来的研究如果能将脑-室变形或顺应性与颅内压相关联，可能会阐明该技术在非侵入性压力监测或非顺应性脑室中的潜在作用。
