Prenatal closure of myelomeningocele is associated with a reduced rate of hydrocephalus treatment. This need for hydrocephalus treatment is positively correlated with fetal ventricular width. When ventricular width is 15 mm or greater, the benefits of prenatal closure, as a method to decrease hydrocephalus treatment, are reduced. Thus, fetal ventricular size is an important factor when counseling families who are considering intrauterine surgery with mitigation of hydrocephalus as the primary goal. This study sought to determine whether imaging modality (ultrasound [US] vs MRI) and interobserver variability were factors in any ventricular size disparity seen on imaging studies.

The imaging studies of 15 consecutive fetuses who underwent prenatal myelomeningocele repair at Children’s Mercy Fetal Health Center, Kansas City, Missouri, were reviewed. All fetuses were imaged with US and fetal MRI; on average (range), procedures were performed 3.8 (0–20) days apart. Three comparisons were performed to analyze interobserver and intermodality variability in ventricular width measurements: 1) retrospective comparison of dictated ventricular widths measured with MRI and US by pediatric radiologists (PRs) and maternal-fetal medicine specialists (MFMs), respectively; 2) blinded measurements obtained with US by PRs versus initial US-based measurements by MFMs, and blinded measurements obtained with MRI by PRs versus initial MRI-based measurements by PRs; and 3) blinded measurements obtained with MRI by PRs versus those obtained with US.

Retrospective comparison showed that measurements with MRI by PRs were on average 2.06 mm (95% CI 1.43–2.69, p < 0.001) larger than measurements with US by MFMs. Blinded measurements with US by PRs were on average larger than dictated measurements obtained with US by MFMs, but by only 0.6 mm (95% CI 0.31–0.84, p < 0.001). When PRs measured ventricular size in a blinded fashion with both US and MRI, the mean width determined with MRI was significantly larger by 2.0 mm (95% CI 1.26–2.67, p < 0.0001).

The ventricular width of these fetuses was larger when measured with MRI than US by an amount that could impact recommendations for fetal surgery. Every center involved in counseling families about the risks and benefits of fetal intervention for spina bifida needs to be aware of these possible imaging-based disparities.

脊髓脊膜膨出的产前闭合与脑积水治疗率降低有关。这种对脑积水治疗的需求与胎儿心室宽度呈正相关。当心室宽度为 15 毫米或更大时，产前闭合术作为减少脑积水治疗的一种方法的好处就会减少。因此，胎儿心室大小是为正在考虑以减轻脑积水为主要目标的宫内手术的家庭进行咨询时的一个重要因素。本研究试图确定成像方式（超声 [US] 与 MRI）和观察者间变异性是否是成像研究中观察到的任何心室大小差异的因素。

回顾了在密苏里州堪萨斯城儿童慈善胎儿健康中心接受产前脊髓脊膜膨出修复的 15 名连续胎儿的影像学研究。所有胎儿均用超声和胎儿 MRI 成像；平均而言（范围），手术间隔 3.8 (0-20) 天进行。进行了三项比较以分析心室宽度测量的观察者间和模态间的变异性：1) 分别由儿科放射科医生 (PR) 和母胎医学专家 (MFM) 对 MRI 和 US 测量的指定心室宽度进行回顾性比较；2) PRs 用 US 获得的盲测值与 MFMs 的基于 US 的初始测量值，以及 PRs 用 MRI 获得的盲测值对比 PRs 的初始 MRI 测量值；

回顾性比较表明，PR 的 MRI 测量值比 MFM 的 US 测量值平均大 2.06 mm（95% CI 1.43–2.69，p < 0.001）。PR 的 US 盲测平均比 MFM 的 US 口述测量大，但仅大 0.6 mm（95% CI 0.31–0.84，p < 0.001）。当 PR 以双盲方式用 US 和 MRI 测量心室大小时，用 MRI 确定的平均宽度显着增大 2.0 mm（95% CI 1.26–2.67，p < 0.0001）。

当用 MRI 测量时，这些胎儿的心室宽度比 US 大，其数量可能会影响对胎儿手术的建议。每个参与就脊柱裂胎儿干预的风险和益处向家庭提供咨询的中心都需要了解这些可能的基于成像的差异。