Department of Radiology, International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Shanghai Key Laboratory of Embryo Original Diseases, Shanghai, China; Department of Radiology, Shandong Medical Imaging Research Institute, Shandong University, Jinan, Shandong, China.
Department of Radiology, Wayne State University School of Medicine, Detroit, MI, USA.
Magn Reson Imaging. 2021 Jul;80:21-25. doi: 10.1016/j.mri.2021.04.001. Epub 2021 Apr 15.
The goal of this study was to estimate venous blood oxygen saturation (SvO2) in the superior sagittal sinus (SSS) in fetal brains with ventriculomegaly (VM) using quantitative susceptibility mapping (QSM).
A radiofrequency spoiled gradient echo sequence was used to evaluate data on 19 fetuses with VM (gestational age(GA): median = 29.9 weeks (range 23 to 37.3 weeks)) and 20 healthy fetuses (GA: median = 30.9 (range 22.7 to 38.7 weeks)) at 1.5 T. Susceptibility weighted images encompassing the entire fetal brain were acquired within 1 min. An iterative, geometry constraint-based thresholded k-space division algorithm was used for generating QSM data of the fetal brain. The venous oxygen saturation was calculated using the magnetic susceptibility of the SSS obtained from the QSM data. Mixed-model analysis of variance and interobserver variability assessment were used to analyze the results.
The median SvO2 values in the entire VM cohort as well as for second and third trimester fetuses (with interquartile range) were: 67.8% (63.2%, 73.6%), 73.1% (69.1%, 77.3%) and 63.8% (59.4%, 68.1%), respectively. The corresponding median SvO2 value in the healthy control group was: 65.3% (58.3%, 68.2%), 67.5% (61.7%, 69.2%) and 60.8% (53.6%, 68.2%), respectively. However, the difference of SvO2 between VM and control groups was not significant at the p = 0.05 level (p = 0.076). The SvO2 was found decreasing significantly with GA in the healthy control group (p < 0.05).
We report for the first time the estimation of cerebral SvO2 in human fetuses with VM using QSM. This measure of oxygen saturation might be beneficial in assessing and monitoring the metabolic status of the fetus in various clinical conditions.
本研究旨在使用定量磁化率映射（QSM）估计脑室扩大（VM）胎儿大脑上矢状窦（SSS）中的静脉血氧饱和度（SvO2）。
使用射频扰相梯度回波序列评估 19 例 VM 胎儿（胎龄（GA）中位数= 29.9 周（范围 23 至 37.3 周））和 20 例健康胎儿（GA：中位数= 30.9 周（范围 22.7 至 38.7 周））的数据。在 1.5T 下，在 1 分钟内采集涵盖整个胎儿大脑的磁敏感加权图像。使用基于迭代、几何约束的阈值 k 空间分割算法生成胎儿脑 QSM 数据。通过从 QSM 数据中获得的 SSS 的磁化率来计算静脉血氧饱和度。采用混合模型方差分析和观察者间变异性评估来分析结果。
整个 VM 队列以及第二和第三孕期胎儿（四分位间距）的中位数 SvO2 值分别为：67.8%（63.2%，73.6%）、73.1%（69.1%，77.3%）和 63.8%（59.4%，68.1%）。健康对照组的相应中位数 SvO2 值分别为：65.3%（58.3%，68.2%）、67.5%（61.7%，69.2%）和 60.8%（53.6%，68.2%）。然而，在 p=0.05 水平上，VM 组与对照组之间的 SvO2 差异无统计学意义（p=0.076）。在健康对照组中，SvO2 随着 GA 的增加而显著下降（p<0.05）。
我们首次报道了使用 QSM 估计 VM 胎儿大脑中的脑 SvO2。这种氧饱和度的测量方法可能有助于评估和监测各种临床情况下胎儿的代谢状态。
