Understanding the early brain: fetal neuroscience
Oxford’s greatest minds are standardising global measurements for fetal brain growth and working with theatre directors to raise awareness of women’s lived experiences of mental illness during pregnancy and after birth. Our experts are shaping global policy and – crucially – improving mental health outcomes for both parent and child.
The fetal brain undergoes significant changes as a baby develops, so Oxford researchers are working to improve fetal ultrasound analysis and better standardise global measurements for fetal brain growth. The Noble Group at the Institute of Biomedical Engineering looks at questions such as why ultrasound scanning and interpretation is so hard to learn, whether AI can simplify ultrasound and whether computers can mimic what a skilled sonographer can do.
A long-standing collaboration between colleagues from the Noble Group and the Oxford Maternal and Perinatal Health Institute (OMPHI), part of the Nuffield Department of Women’s and Reproductive Health, has led to a number of advancements in this area. One such collaboration proposed an automated framework for predicting age and neurodevelopmental maturation of a fetus based on 3D ultrasound brain images. This is particularly important, as accurate estimation of gestational age is essential to prenatal care. The team, which included Professor Ana Namburete (founder of the Oxford Machine Learning in Neuroimaging Lab), Professor Alison Noble and Professor Aris Papageorghiou, developed a new feature-based model that had never before been attempted. Their analysis showed that the model did not just estimate chronological age, but also the neurodevelopmental stage of the fetus based on brain structure.
Neuroimaging - Any non-invasive means of generating images of a living brain. These are used for diagnosis of brain disease and injury and can also be obtained to show activity in the brain as various mental tasks are being performed. A later collaboration between these colleagues, which also included Postdoctoral Researcher Jianbo Jiao from the Department of Engineering Science, looked at second-trimester anomaly screening in the fetal brain. While fetal brain magnetic resonance imaging (MRI) offers detailed images of brain development, they are not used in the second trimester due to time and cost limitations. In this case, ultrasound (US) is then employed. Expert sonographers are adept at reading ultrasound images, but MR images are easier for non-experts to interpret. By developing methods to synthesise MR-like fetal brain images from ultrasound ones, the researchers hope their framework can be useful when communicating ultrasound findings to both obstetricians and patients. Working with Dr Lorenzo Venturini (DPhil 2022), Professors Namburete, Noble and Papageorghiou also co-authored a paper exploring the use of convolutional neural networks, or CNNs, for the segmentation of multiple fetal brain structures in 3D ultrasound images.
Convolutional neural network (CNN) is a machine-learning technique that can learn to distinguish important boundaries and objects; they are increasingly popular in the segmentation of fetal ultrasound images .The proof-of-concept paper looked at whether the researchers could apply a machine-learning based method for automated segmentation of multiple fetal brain structures. This sort of accurate detection can track brain development through gestation, helping predict fetal health outcomes. Additional work on the topic of CNNs has been conducted in collaboration with the Big Data Institute, the Wellcome Centre for Integrative Neuroimaging and the INTERGROWTH-21st Consortium. Titled BEAN (Brain Extraction and Alignment Network), the collaborative paper presents a multi-stage CNN that allows for the actual shape of the brain to be analysed, which is fundamental to tracking how the brain matures.
Setting standards for growth
The INTERGROWTH-21st (International Fetal and Newborn Growth) Consortium, which is dedicated to improving perinatal health, also looked at creating standards for five fetal brain structures. Fetal brain anatomy is assessed routinely as part of the 20-week anomaly scan. The measurements are assessed against one of several reference charts. However, these have limitations, and there can also be a lack of consistency in the interpretation of ultrasound images of the fetal central nervous system. Using a study population consisting of women at low risk of adverse pregnancy and perinatal outcomes, the researchers produced international size standards for fetal brain ultrasound measurements.
Cerebellar - Relating to the part of the brain at the back of the skull that coordinates and regulates muscular activity
Analysing fetal development
In addition to setting standards for fetal growth, experts at Oxford are analysing some of the ways in which fetal development can be affected. For example, a paper co-authored by Professor Aris Papageorghiou looked at the development of the fetal nervous system, and how this could be affected by Brain-Derived Neurotrophic Factor (BDNF) levels in second trimester amniotic fluid. This is important as abnormalities in fetal growth can be linked to maternal, fetal and neonatal adverse outcomes. A paper co-authored by Professor Aris Papageorghiou, Professor Ana Namburete and colleagues from Leiden University also analysed fetal brain development to help understand whether changes in fetal circulation contributes to the delay in maturation of the cortex in fetuses with congenital heart defect (CHD).
Depression and anxiety in pregnancy
Experts at Oxford are not only working to improve aspects of fetal neuroscience, but also to improve the mental health and wellbeing of expectant mothers during pregnancy.