The world’s most powerful MRI machine has started proving its worth, by scanning living human brains. The resulting images give an ultra high resolution glimpse into the brain, which will help us better understand the nature of consciousness and treat neurodegenerative diseases.
Developed by the French Alternative Energies and Atomic Energy Commission (CEA), the Iseult MRI machine packs a magnetic field strength of 11.7 Teslas (T). By comparison, conventional MRI machines in wide use in hospitals today are usually 1.5 or at most 3 T.
The main benefit of that extra power is that much higher resolution images of the brain can be taken, much quicker. In just four minutes, Iseult can capture images down to 0.2 mm (0.008 in) of brain tissue horizontally, in 'slices' just 1-mm (0.04-in) thick. That volume is the equivalent of a few thousand neurons at a time.
For conventional MRI machines to take images of this resolution, patients would need to lie perfectly still for more than two hours – the slightest movement would blur the shot. That of course just isn’t feasible.
Also boosting comfort is the 90-cm (35.4-in) wide 'hole' for patients to stick their heads in. That might not seem like a huge increase over the usual 60-to-70 cm (23.6-to-27.6 in), but the extra headroom can help make the experience less claustrophobic.
Iseult was tested a few years ago on pumpkins, but now it’s scanned its first human brains, belonging to 20 healthy volunteers. The stunning images demonstrate the potential for the new MRI technology to reveal previously unattainable information about how the brain works, including how it encodes mental representations, and which neuronal signatures are associated with consciousness itself.
Besides those existential questions, Iseult should also help scientists understand, diagnose and treat neurodegenerative diseases like Alzheimer’s and Parkinson’s. It should be able to detect chemical signatures that are usually too weak to be seen with regular MRI scans, including molecules like glucose and glutamate, which are involved in brain metabolism and disorders of which can be involved in conditions like gliomas and neurodegeneration. It will also be able to track the distribution of lithium in the brain, which is used to treat bipolar disorders.
Thanks to its complexity, Iseult is far larger than other MRI machines. It measures 5 m (16.4 ft) long and wide, weighs 132 tons and is made with 182 km (113 miles) of superconducting wires. To keep the magnets cooled to the required -271.35 °C (-456.43 °F) takes some 7,500 liters (1,981 gallons) of liquid helium. That size, complexity and no doubt cost might limit where the Iseult MRI machine can be used, but hopefully it will be beneficial enough to go into service in some specialty facilities soon.
The team discusses the tech in the video below.
Source: CEA
The Iseult project started in 2004, the design was mostly complete by 2010, with construction starting in 2013, installation taking place during 2017, the machine reached full magnetic field strength in 2019, and commissioning took until 2023 before the system was ready for scientific use.
Because building this huge machine has been a 20 year endeavour, the technology has moved on during the development. In particular, this system uses conventional niobium-titanium alloy low temperature superconductor (LTS) with immersion cooling in liquid helium. This necessitates a very large cryostat (5m diameter x 5m length, 132 tonne weight), as well as approximately 1000 kg of liquid helium.
LTS technology has the advantage of being well understood, with considerable industrial experience. However, high temperature superconductors are commercially available, with solutions available to some of the major difficulties of building magnets with these materials (e.g. wire joints have proven extremely difficult with HTS conductors).
Radboud University in the Netherlands, has recently commenced a project to build a 14 T whole body MRI system using HTS technology. The Radboud machine is expected to be 1.5m in diameter, 2m long and weigh 15 tonnes, and use "dry" cooling (no liquid helium).
The brain is physical and consciousness is meta-physical.
There isn't a scientist alive that can prove how consciousness arises from molecules that comprise cells that make up brain tissue.
Read "Irreduicable Mind".