Academic Unit of Radiology, University of Sheffield, Sheffield, UK.
Clinical Trials Research Unit, School of Health and Related Research, University of Sheffield, Sheffield, UK.
Clin Radiol. 2019 Jul;74(7):527-533. doi: 10.1016/j.crad.2019.03.010. Epub 2019 Apr 12.
To estimate the rate of unexpected brain abnormalities detected by in utero magnetic resonance imaging (iuMRI) in fetuses without abnormalities at ultrasonography (USS).
A prospective cohort study of pregnant women whose fetus had no structural brain (or body) abnormalities recognised on antenatal ultrasonography. Women were recruited from 12 centres across the UK and underwent iuMRI at 18 gestational weeks or more in the [blinded for review]. The imaging studies were reviewed by an experienced neuroradiologist. The positive and negative predictive values of both USS and iuMRI have been calculated by combining the results of this study with the results from the main [blinded for review] study.
One hundred and ninety-eight pregnant women were recruited and underwent iuMRI of 205 fetuses. Brain abnormalities were shown on iuMRI in two fetuses that were not recognised on USS (one case of a focal cortical abnormality and one case of mild ventriculomegaly). The negative predictive value for USS was 99.5% and 100% for iuMRI.
To the authors' knowledge, this is the first study comparing USS and iuMRI in low-risk pregnancies. USS has a comparatively high rule-out for fetal brain abnormalities and should remain the screening tool of choice.
评估在超声检查（USS）未见异常的胎儿中，通过宫内磁共振成像（iuMRI）检测到意外脑异常的发生率。
这是一项对孕妇的前瞻性队列研究，其胎儿在产前超声检查中未发现有结构脑（或身体）异常。这些女性来自英国 12 个中心，在[审查中为盲法]进行了 18 孕周或以上的 iuMRI。由一位有经验的神经放射科医生对成像研究进行了评估。通过将这项研究的结果与主要[审查中为盲法]研究的结果相结合，计算了 USS 和 iuMRI 的阳性和阴性预测值。
共招募了 198 名孕妇，并对 205 名胎儿进行了 iuMRI。在 2 名在 USS 上未识别出脑异常的胎儿中（1 例为局灶性皮质异常，1 例为轻度脑室扩大）显示出 iuMRI 脑异常。USS 的阴性预测值为 99.5%，iuMRI 的阴性预测值为 100%。
据作者所知，这是第一项比较低风险妊娠中 USS 和 iuMRI 的研究。USS 对胎儿脑异常的排除率较高，应继续作为首选筛查工具。
