Until now, if you wanted to study how babies' brains functioned and developed, there was no alternative to magnetic resonance imaging. Unfortunately, putting babies in an MRI machine and keeping them still isn’t exactly easy. But a French team has just developed a new ultrasound neuroimaging technique. How is this scientific innovation going to revolutionize the way we observe babies’ neuronal activity?

Even today, apart from data from neuroimaging and electroencephalography (which doesn't produce functional images), "we're completely in the dark when it comes to brain activity and development in babies,” says Mickael Tanter (who led the research team). Moreover, with very young children, clinical use of these techniques is very difficult. This is why his team wanted to make up for this shortcoming in the study of brain development in babies by developing a new neuroimaging technique using ultra-sensitive ultrasound.

How does it work? Imagine a sort of augmented ultrasound that, by recording images at a very high speed, would make it possible to view cerebral blood flows and to map their variations with great precision. This is fUSI (functional ultrasound imaging). As Professor Olivier Baud at the Robert-Debré Hospital in Paris points out: "the technique is based on the concept of neurovascular coupling." This method, invented in 2011, was recently tested in babies and the results were published by the research team (INSERM, CNRS, ESCPI) in Science Translationnal Medicine.

Their study shows that the fUSI technique is effective because the micro-variations in cerebral blood volume seen in newborns according to two stages (restless, calm) are correlated with well-known EEG (electroencephalography) data. In two infants with abnormal cortical development (epilepsy), data (with a spatial resolution of 15 micrometers) was produced using fUSI, helping to locate the focus of the seizures.

This new non-invasive imaging method can be used in newborns because their cranial cavity is still not reinforced. Because the bone is still very thin, the ultrasound can traverse the skull. As the baby grows, this method will become more and more difficult to use, as M. Tanter points out: "there’s not much we can do technically to keep the waves from being absorbed by the bone.” However, in adults, the method could consist of going through the temple or the foramen magnum, the hole located at the base of the skull.

In conclusion, while the commercialization of the fUSI technique (a portable device) isn't going to happen right away, according to the authors, "we are on the edge of a revolution in the domain of cerebral monitoring" that could help with early detection of developmental disorders, and particularly autism.