Swedish researchers have developed a portable helmet that uses microwaves to quickly determine whether a person has had a stroke.
How well a patient recovers from a stroke is linked to how quickly the stroke is diagnosed and treatment is started. During the acute stage of a stroke around two million brain cells die every minute due to lack of oxygen. The faster the oxygen supply can be restored, the more brain (and therefore brain function) can be restored. The financial cost of strokes is enormous: estimated to be around 64 billion in Europe in 2010 alone. However, the human cost is even more devastating, with five million people dying each year and five million left permanently disabled.
There are two types of stroke: 80 percent of strokes are caused by clots and 20 percent are due to bleeding on the brain. If you are unlucky enough to have the clot-type (ischemic stroke), you need to be given a drug that dissolves clots within a few hours -- up to 4.5 hours -- in order to be effective. A haemorrhagic stroke -- where there is a bleed on the brain -- requires different treatment.
Usually strokes are diagnosed using a CT or MR scan, but because of how busy hospitals are it's often hard to get a diagnosis within the necessary window. As a consequence, less than 10 percent of patients get the anti-clotting treatment.
Strokefinderis a helmet-like device developed by Medfield Diagnostics -- a spinout from Chalmers University of Technology -- that uses a technique called microwave tomography in order to diagnose strokes. The helmet is covered in microwave antennas, and one antenna at a time sends a signal that scatters in the brain matter while the other antennas receive data. The received signals are then processed in order to generate a picture of the brain. The device is made up of much simpler components that traditional diagnostic techniques making it a much more accessible technology.
The device has been subjected to testing with 45 patients. An early prototype involved a modified bike helmet and was found to be able to differentiate between the two types of stroke accurately some of the time. The team has since refined the device, building a custom-helmet that better adapts to different skulls, and it's been tested in a local hospital. The plan is to carry out a large-scale study in order to improve the predictive power of the algorithms.
Mikael Perrson from the Department of Signals and Systems at Chalmers University of Technology told Wired.co.uk that the technology was born out of studies from a decade ago where his team was studying how electromagnetic fields from mobile phones were penetrating through the brain. "We realised by looking at the simulations how the details of the brain were attracting the wave propagation," he said, meaning that it was possible to detect changes in the brain.
This led to the development of the first prototype, before Medfield Diagnostics was spun out of the university to develop the second prototype. The third generation product -- to be released in autumn of 2014 -- will be CE-marked, meaning that it can be sold on the open market.
"It will be more like a pillow you rest your head on, without all of the cables. Also it will have a wireless connection to an iPad or external devices so it's much more geared towards ambulance use," he explains.
There are a number of different technologies being trialled for portable stroke detection including ones that use near-infrared, ultrasound and impedance methods. "From a fundamental point of view microwave tech is the most promising because it readily penetrates the skull bone so has some fundamental advantages which other modalities have."
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Speed up stroke diagnosis with this portable microwave helmet