目的:报告在超声诊断为轻度或中度脑室增宽(VM)的胎儿中,仅在产前磁共振成像(MRI)检测到的额外中枢神经系统(CNS)异常的发生率,根据所采用的超声协议的类型(专用神经超声检查与胎儿大脑的标准评估),并探讨胎儿MRI在检测此类异常方面的诊断性能是否受检查时的胎龄以及心室扩张的偏侧和程度的影响。
方法:MEDLINE,EMBASE,搜索CINAHL和Clinicaltrials.gov,以研究报告对超声诊断为轻度或中度VM(心室扩张10-15mm)的胎儿进行产前MRI评估的研究。仅在MRI上检测到的其他异常被分类为call骨,间隔,后颅窝,白质,脑室内出血,皮质,脑室周围异位症,脑室周围囊肿或复杂畸形。在专门的神经超声检查中诊断出的胎儿之间比较了其他异常的发生率,定义为对胎儿大脑的详细评估,根据国际妇产科超声学会指南,和那些在标准胎儿大脑评估中被诊断出来的人。计算并比较早期(妊娠24周时或之前)和晚期(24周后)MRI的胎儿之间仅在出生时检测到的额外中枢神经系统异常的发生率。根据侧方性(单侧与双侧)和程度(轻度与中度,定义为10-12和13-15毫米的心室扩张,分别)心室扩张。探讨了MRI评估是否导致产前管理发生重大变化。使用比例的随机效应荟萃分析。
结果:16项研究(1159例胎儿)纳入系统评价。总的来说,MRI在10.0%(95%CI,6.2-14.5%)的胎儿中检测到超声未发现的异常。然而,根据超声评估的类型对分析进行分层时,仅在MRI上检测到的相关异常率为5.0%(95%CI,3.0~7.0%),而在轴平面对胎儿脑进行标准评估的病例中,仅在MRI上检测到的相关异常率为16.8%(95%CI,8.3~27.6%).仅在出生时发现并在产前MRI上错过的额外异常的总体率为0.9%(95%CI,0.04-1.5%)(I2,0%)。仅在出生后进行胎儿MRI检查时,相关异常的发生率没有差异,与之后相比,妊娠24周(P=0.265)。中度胎儿的MRI检测到相关中枢神经系统异常的风险高于轻度VM的胎儿(比值比,8.1(95%CI,2.3-29.0);P=0.001),虽然双边的人没有区别,与单边相比,扩张(P=0.333)。最后,围产期管理的重大变化,主要是由于父母的要求而终止妊娠,MRI检测到相关异常后,在接受专用神经超声检查的胎儿中有2.9%(95%CI,0.01-9.8%),而接受标准评估的胎儿中有5.1%(95%CI,3.2-7.5%)。
结论:在接受专门神经超声检查的胎儿中,仅在MRI上检测到的CNS异常率低于以前报道的。早期MRI在识别其他中枢神经系统异常方面具有出色的诊断性能,虽然这项审查的结果表明,在妊娠晚期进行MRI可能与某些类型的异常的更好的检出率有关,比如皮质,白质和颅内出血性异常.版权所有©2018ISUOG。由JohnWiley&SonsLtd.发布.
OBJECTIVE: To report the rate of additional central nervous system (CNS) anomalies detected exclusively on prenatal magnetic resonance imaging (MRI) in fetuses diagnosed with isolated mild or moderate ventriculomegaly (VM) on ultrasound, according to the type of ultrasound protocol adopted (dedicated neurosonography vs standard assessment of the fetal brain), and to explore whether the diagnostic performance of fetal MRI in detecting such anomalies is affected by gestational age at examination and laterality and degree of ventricular dilatation.
METHODS: MEDLINE, EMBASE, CINAHL and Clinicaltrials.gov were searched for studies reporting on the prenatal MRI assessment of fetuses diagnosed with isolated mild or moderate VM (ventricular dilatation of 10-15 mm) on ultrasound. Additional anomalies detected only on MRI were classified as callosal, septal, posterior fossa, white matter, intraventricular hemorrhage, cortical, periventricular heterotopia, periventricular cysts or complex malformations. The rate of additional anomalies was compared between fetuses diagnosed on dedicated neurosonography, defined as a detailed assessment of the fetal brain, according to the International Society of Ultrasound in Obstetrics and Gynecology guidelines, and those diagnosed on standard fetal brain assessment. The rate of additional CNS anomalies missed on prenatal MRI and detected only at birth was calculated and compared between fetuses that had early (at or before 24 weeks\' gestation) and those that had late (after 24 weeks) MRI. Subanalysis was performed according to the laterality (uni- vs bilateral) and degree (mild vs moderate, defined as ventricular dilatation of 10-12 and 13-15 mm, respectively) of ventricular dilatation. Whether MRI assessment led to a significant change in prenatal management was explored. Random-effects meta-analysis of proportions was used.
RESULTS: Sixteen studies (1159 fetuses) were included in the systematic
review. Overall, MRI detected an anomaly not identified on ultrasound in 10.0% (95% CI, 6.2-14.5%) of fetuses. However, when stratifying the analysis according to the type of ultrasound assessment, the rate of associated anomalies detected only on MRI was 5.0% (95% CI, 3.0-7.0%) when dedicated neurosonography was performed compared with 16.8% (95% CI, 8.3-27.6%) in cases that underwent a standard assessment of the fetal brain in the axial plane. The overall rate of an additional anomaly detected only at birth and missed on prenatal MRI was 0.9% (95% CI, 0.04-1.5%) (I2 , 0%). There was no difference in the rate of an associated anomaly detected only after birth when fetal MRI was carried out before, compared with after, 24 weeks of gestation (P = 0.265). The risk of detecting an associated CNS abnormality on MRI was higher in fetuses with moderate than in those with mild VM (odds ratio, 8.1 (95% CI, 2.3-29.0); P = 0.001), while there was no difference in those presenting with bilateral, compared with unilateral, dilatation (P = 0.333). Finally, a significant change in perinatal management, mainly termination of pregnancy owing to parental request, following MRI detection of an associated anomaly, was observed in 2.9% (95% CI, 0.01-9.8%) of fetuses undergoing dedicated neurosonography compared with 5.1% (95% CI, 3.2-7.5%) of those having standard assessment.
CONCLUSIONS: In fetuses undergoing dedicated neurosonography, the rate of a CNS anomaly detected exclusively on MRI is lower than that reported previously. Early MRI has an excellent diagnostic performance in identifying additional CNS anomalies, although the findings from this
review suggest that MRI performed in the third trimester may be associated with a better detection rate for some types of anomaly, such as cortical, white matter and intracranial hemorrhagic anomalies. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.