One of the major breakthroughs in medical science during the last two decades of the 20th century was the introduction of magnetic resonance imaging (MRI). It’s not surprising, therefore, that the developers of MRI – Paul Lauterbur and Peter Mansfield – were awarded the Nobel Prize for Medicine in 2003. Two of the major drawbacks of MRI are its cost – $1.5 million – and bulky size, requiring a dedicated room with magnetic shielding for the supercomputing electromagnets. In today’s issue of Science, a freely available article has been published that reviews the efforts to address these drawbacks.
The publicly listed company Hyperfine received FDA clearance for its Swoop MRI device in August 2020 and since then has been conducting extensive clinical testing. Seen above right (© Yale School of Medicine) is a comparison of the brain scan of a patient with a haemorrhage acquired by Swoop (left) compared with a conventional MRI device (right). Clearly the spatial resolution of Swoop is much coarser than conventional MRI although the haemorrhage is clearly visible in both.
Seen at left is Swoop (© Derek Dudek) which weighs 630kg, has a permanent magnet with field strength of just 64 milli-tesla, and can be propelled around the hospital and moved to a patient’s bed in the ward. The system costs $250,000 – about 5 times the original target price – with Hyperfine reporting the sale of 100 machines, mostly in the USA. One knowledgeable commentator has suggested it’s not yet clear if there’s a market for a scanner with lower resolution, saying, “The real challenge is going to be convincing doctors to start using it.”
A recent entrant to this field is a group from the Netherlands who have built a system that differs markedly from Swoop with a design that implements a Halbach array to produce a uniform magnetic field. They have licensed their technology to a private company, Multiwave Technologies in Switzerland, that plans to apply for FDA approval in 2023.
Andrew Webb, one of the inventors of the system, said, “We made a decision that we were not going to patent things [and so] everything is going to be open source.” This means that anyone can download their design from the internet and build a working scanner. To encourage this concept, the Dutch team shipped a scanner, packaged as a kit, to a children’s hospital in Uganda. In September 2022, Webb and his colleagues flew to the East African country to assemble the scanner, working with local biomedical engineers (seen right). Clearly, this is MRI for the little guys!