Peel our brains with unprecedented precision. This is what Iseult promises, a magnetic resonance imaging (MRI) device designed by the Atomic Energy and Alternative Energies Commission (CEA), whose first anatomical images of the human brain were unveiled on Tuesday, April 2, on the Saclay site. In 2021, the 11.7 Tesla of its magnetic field had already revealed the inside of a pumpkin, to mark its entry into an operational phase after twenty years of development. Since then, CEA teams have cautiously moved to observe their first human subjects.
“The images are incomparably clear! », is pleased with Nicolas Boulant, responsible for the Iseult project at CEA. To obtain anatomical images that provide the resolution of Iseult’s in four minutes of observation – 0.2 mm in plane and 1 mm deep – it would be necessary to spend two hours in a hospital-grade 3T scanner. A completely theoretical comparison, because the patient’s movements would then blur the image.
If the transition from pumpkin to human has taken so long, it’s because with Iseult we’re entering uncharted territory of cerebral exploration. “It was necessary to prove to the health authorities that such an intensity of the magnetic field has no effect on health”, explains Nicolas Boulant. The previous record was 10.5 Tesla on an American machine in Minneapolis. For verification purposes, tests were therefore carried out on 20 healthy adult volunteers balance, cognition, brain tissue temperature, genotoxicity, etc. A nocébo study was even conducted, where volunteers, without their knowledge, were subjected to a session at zero Tesla, to see if the machine, “which can be intimidating”notes Nicolas Boulant, could cause a psychological bias. “We didn’t see anything at allassures the physicist. It was a crucial step to see if we could actually do it an explorer of the human brain. »
“Deciphering the Neural Code”
A new phase will now begin in which the acquisition of data will be further refined according to the different imaging modalities that MRI offers: anatomical data, but also functional data – that is, visualizing the brain areas activated by this or that cognitive activity. It will also be possible to perform so-called “diffusion” imaging, which highlights the neuronal bundles that connect the different parts of the brain. The intensity of the magnetic field should also make it possible to detect invisible compounds in lower fields, such as lithium, used in bipolar disorder, and glucose and glutamate, small molecules involved in brain metabolism.