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Aim: To estimate the rate of unexpected brain abnormalities detected by in utero magnetic resonance imaging (iuMRI) in fetuses without abnormalities at ultrasonography (USS).Materials and Methods: 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.Results: 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.Conclusions: 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. [ABSTRACT FROM AUTHOR]

Aim: The study aimed to describe the features of magnetic resonance imaging (MRI) in fetuses with tethered-cord syndrome (TCS) or lower spinal cord (LSC) and to analyse the clinical outcomes and complications during follow-up.Materials and Methods: This is a retrospective study of fetuses diagnosed with TCS or LSC using MRI from January 2015 to August 2019. The average gestational week (GW) at MRI examination was 25.46 ± 4.73 GW (range: 21-39 GW). MRI was used1 to identify the anatomical landmarks of the spine2; to measure the width of the conus medullaris and record the ending position of the LSC3; and to analyse other neurological deformities. The diagnostic results between MRI and ultrasonography (US) were compared.Results: A total of 38 fetuses with suspected intracranial or spinal lesions on US or MRI were included. Among all fetuses, 17 fetuses were diagnosed with LSC or TCS without associated anomalies. Twenty-one fetuses had complications of central nervous system (CNS) anomalies, one fetus also had a diagram hernia, and one fetus had an inverse foot. MRI provided more diagnoses than US in nine fetuses. Two cases of diastematomyelia detected on MRI were missed on US. The capability of MRI was comparable with that of US in terms of displaying spina bifida.Conclusion: In the present study, fetal MRI showed better performance than US for depicting TCS and related CNS abnormalities. MRI provided clinicians with additional information in terms of prenatal counselling and management. [ABSTRACT FROM AUTHOR]

Aim: To describe a new finding in fetuses with Chiari 2 malformations recognised at in utero (iu) magnetic resonance imaging (MRI), specifically T2 prolongation (high signal) in the cerebellar vermis.Materials and Methods: This was a prospective observational study of iuMRI studies performed at two time points on 20 fetuses with Chiari 2 malformations and 10 control fetuses at the same time points. High T2 signal in the cerebellar vermis was noted and correlated with posterior fossa dimensions was assessed.Results: High T2 signal in the cerebellar vermis was found in over half of the fetuses with a Chiari 2 malformation, but was not correlated with the degree of reduction in size of the bony posterior fossa.Conclusion: The present findings suggest that abnormal high T2 signal in the cerebellum is common in fetuses with Chiari 2 malformations and although the cause of the signal change is not known at present it may represent vasogenic oedema as a result of restricted venous drainage. [ABSTRACT FROM AUTHOR]