The August issue of Ultrasound in Obstetrics & Gynecology includes a series of papers on different aspects of fetal brain imaging, including studies on neurodevelopmental outcome and the role of magnetic resonance imaging in fetal isolated mild ventriculomegaly, and the sonographic assessment of the Slyvian fissures and their development in fetuses with cortical maldevelopment. Articles on other topics include a systematic review, with an accompanying video abstract, on the effectiveness on fertility outcome of tubal flushing using different contrast media, and a study on core principles for parental engagement in the perinatal mortality review process.
Isolated mild ventriculomegaly
Some cases with ventriculomegaly (VM) that appears prenatally to be isolated are found to have other abnormalities postnatally. In the presence of associated abnormalities, the prognosis is poor. Thorup et al. estimated the prevalence of neurodevelopmental disorders at 2–7 years of age in children believed to have isolated mild VM prenatally. Of the children, 12.3% were found postnatally to have an additional finding. In those with postnatally confirmed isolated mild VM, there was an increased risk of neurodevelopmental disorder, as compared with the reference population, although the absolute risk was low and there were no cases of intellectual disability or cerebral palsy (view the accompanying Journal Club slides).
Whether isolated mild VM should be considered an indication for magnetic resonance imaging (MRI) is a controversial issue. In a systematic review, Di Mascio et al. investigated the rate of additional central nervous system (CNS) anomalies detected exclusively on prenatal MRI in fetuses diagnosed with isolated mild or moderate VM on ultrasound, according to the type of ultrasound protocol adopted, and whether this rate was affected by gestational age at examination and the laterality and degree of ventricular dilatation. Overall, MRI detected an anomaly not identified on ultrasound in 10.0% of cases. The rate was lower when dedicated neurosonography, rather than standard assessment of the fetal brain, was performed. Although early MRI is reliable, a third-trimester ultrasound scan may detect conditions potentially missed on a second-trimester scan.
Building upon these findings, Paladini et al. reviewed their recent experience of isolated mild VM and cases published in the literature in order to investigate possible factors responsible for the discrepancy in the reported usefulness of MRI in the assessment of isolated mild VM. Along with specialty of the first author and atrial width, transabdominal, as opposed to transvaginal, ultrasound was associated with an increased risk of an additional clinically relevant finding detected on MRI. The authors propose a gold standard for assessment of pregnancies in which fetal isolated mild VM is suspected, which, along with improved training, may reduce the rate of an additional finding detected on MRI to 1.6%.
Sonographic assessment of Sylvian fissures
The anatomical features of the Sylvian fissures in the fetus have been observed to change with advancing gestation, although these changes have mostly been evaluated subjectively. Poon et al. evaluated the normal development of the Sylvian fissures in the anterior coronal view of the fetal brain at 18–30 weeks’ gestation by transvaginal 3D ultrasound and developed reference ranges of measurements of the right and left Sylvian fissure angles, finding assessment of the Sylvian fissure angles to be highly reproducible. Using this technique and the references ranges developed in this study, Pooh et al. evaluated Sylvian fissure development in fetuses with malformation of cortical development (MCD). It was found that the Sylvian fissures have delayed development in most fetuses with MCD prior to the diagnosis of the condition. Sylvian fissure angle may be an indicator for subsequent development of cortical malformation before the gyri and sulci become obvious.
Articles on other topics
Effectiveness on fertility outcome of tubal flushing with different contrast media: systematic review and network meta-analysis
Tubal flushing constitutes an essential part of the fertility workup and has been used in several different techniques to visualize tubal patency. In this systematic review of randomized controlled trials, Wang et al. compared, in women with infertility, the effectiveness and safety of tubal flushing using different contrast media, and evaluated the effectiveness of tubal flushing on fertility outcome over time. It was found that tubal flushing using oil-based contrast medium may increase clinical pregnancy rates within 6 months and subsequent live-birth rates, compared with tubal flushing using water-based contrast medium and compared with no intervention. Evidence on fertility outcomes beyond 6 months was inadequate to draw firm conclusions. View the accompanying video abstract:
UOG video abstract on tubal flushing
PARENTS 2 study: consensus report for parental engagement in the perinatal mortality review process
The PARENTS 1 study found that parents would endorse the opportunity to give feedback to the perinatal mortality review (PNMR) process. In subsequent focus groups, healthcare professionals were positive about parental engagement, although they considered that there may be significant challenges. Bakhbakhi et al. conducted the PARENTS 2 study to develop core principles for parental engagement in the PNMR process in the UK. Using a Delphi technique, key stakeholders reached consensus on 12 core principles to make the PNMR process feasible, meaningful and robust. The core principles included face-to-face explanation of the PNMR process, opportunity for parents to nominate a suitable advocate, formal documentation of responses to parents’ comments, translation of action plans into lessons learnt, and production of a plain-English summary for parents following the meeting.
Coming up in the next issue…