Leiden University Medical Centre’s radiology department is on the third floor, but MRI professor Andrew Webb and his team work on the ground floor. That’s because their favourite toy weighs more than thirty-five thousand kilos, so it needs some solid support.
The 7-Tesla MRI scanner is one of Leiden University Medical Centre’s showstoppers. The world does not have many of these devices, which produce images of parts of the human body in very high resolution. When Mare came to visit, a patient with hearing problems, whose doctor wanted to know the exact lay of his auditory nerve without cutting his ear open, was in it. It’s a high tech, high skill trick, because that nerve is about one millimetre thick.
"That’s how we do things here", says Webb. "This apparatus cost 8.5 million Euros, and its powerful magnetic field needs liquid helium that’s a few degrees above absolute zero. Only extremely highly trained staff can operate it and if it breaks down, someone from Philips in Noord Brabant has to come in to repair it, which is not very convenient if you’re working at hospital in Uganda."
Not surprisingly, in all of Uganda – with a population of 38 million – there are six times fewer MRI devices than at LUMC, i.e. one. Webb wants that to change. "Here, we have an incredibly complicated device but we convert the data it produces into images using a computer that is, in essence, comparable to an ordinary home PC. Our idea is to turn things around by using a simpler system, that can do less but performs more powerful calculations."
"We" is a joint venture between Webb and two people from Delft University of Technology: micro-electronics expert Rob Remis and Professor of Applied Mathematics Martin van Gijzen. The three were recently awarded an "Open Mind" subsidy for their idea for a cheap MRI. Those subsidies are relatively small grants – 50,000 Euros – for original, feasible ideas.
On Webb’s table, there are some plastic rings set around a circle of small, cubed magnets, just ordinary magnets like you get on fridge doors: they cost about one Euro each. If you have enough of them, together they will create a magnetic field of 0.1 to 0.2 Tesla, the force the Leiden-Delft team is aiming for, for now. "Our aim is not to produce something as good as the equipment we have here; we want to make something that is just good enough", Webb explained. For the majority of medical diagnoses, the images do not need to be accurate right down to the last millimetre."
"Actually, the question is, how weak can the magnet be?" he added. "The designs and prototypes fly back and forth between our three groups, to see what we can get away with. Martin might specifically say: ‘We need a magnet that’s twice a strong as this.’" They plan to have produced a working prototype within twelve months. "It should be robust, transportable and good enough to use for diagnostics", Van Gijzen sums up their goal.
For example, a weak magnet would allow doctors to diagnose hydrocephalus, a common problem in infants in developing countries. There are many things that cause cerebrospinal fluid to build up in the brain, although in Africa, it is usually caused by infections. It can lead to crossed eyes, epilepsy, mental deficiencies or, in children, a rapidly expanding skull. It is best to discover it before the head starts to swell. If swelling sets in, the "water" (i.e. the cerebrospinal fluid) needs to be drained and you need to make sure the tube doesn’t get blocked up.
"Hydrocephalus is a relatively easy imaging problem", Van Gijzen explains: the skull contains large spots of water and water is precisely one of the things that are visible in an MRI scan.
A weak magnetic field produces a weaker signal and more disturbance, so Van Gijzen’s maths need to compensate for that. "One of the things we want to try is to revolve the magnetic ring to produce different images which we can then combine to create images with a higher resolution." He also suspects that faster computers could compensate for the effects of a non-homogeneous field.
The final design is to be made fully public, both the construction plans and the software, which means that a local factory in Africa could manufacture and maintain cheap MRI scans. Van Gijzen adds: "We want that knowledge to be accessible in Africa. We don’t want to drop a chunk of technology on them that they can’t use."
Why would a professor with an 8.5-million bit of kit still make an effort to get a fifty-thousand Euro subsidy? "Right now, my group alone is working with 15 different grants – a total of around ten million Euros", Webb continued. It’s all geared towards making diagnoses for rich people. That’s great, of course, and important too, but that doesn’t work for eighty per cent of the world’s population. But the money in those grants has been allocated to specific projects; I can’t say: ‘Hey, you gave me money for brain research but I spent it on building a cheap low-field MRI.’
"Besides, it gives us old dogs the chance to get back into the lab and start from scratch. We can’t do that very often anymore; you can’t fix your car yourself nowadays because it’s run by software. But it’s the reason why we wanted to be engineers, once upon a time."