Scientists hope a portable brain scanner that uses Bluetooth radio technology could lead to stroke victims receiving treatment much more quickly.
Strokes are caused by bleeds or clots in the brain
The University College London team hope the device could be used onboard ambulances to diagnose people thought to have had a stroke.
Currently stroke patients have to wait until they arrive at hospital to have a scan before receiving treatment.
More than 130,000 people a year in England and Wales have a stroke.
About 60,000 of those die.
The scanner would send the images via Bluetooth - which swaps data via short-wave radio - to a computer onboard the ambulance to allow paramedics to diagnose the cause of the stroke, or send it to consultants at the hospital if they are unable to identify it.
Treatment for strokes varies depending on whether it is caused by a bleed in the brain or a blood clot in the carotid artery which leads to the brain.
Clot-busting drugs need to be administered within three hours of an attack, but they can make the damage worse if the stroke has been caused by a bleed.
Stroke patients have to wait until they arrive at hospital for a CT or MRI scan to diagnose the cause, but doctors say valuable time can be lost while this is done.
Dr Alistair McEwan said the device could also be used to identify epileptic seizures and potentially migraines, tumours, heart, lung and liver conditions in the future.
WHAT IS BLUETOOTH?
Short-range radio technology that allows data to be swapped
In hand-held computers and mobile phones as can only exchange information to devices in close proximity
Named after Harald Bluetooth, a 10th century Danish king famed for uniting his nation with Norway
"My plan is to design a device that can be simply placed on a patient's head to quickly provide an accurate assessment to allow treatment to start immediately.
"For strokes, speed is really of the essence so beginning treatment as soon as possible will save lives and unnecessary brain damage."
Andrew Proctor, from charity Action Medical Research, which gave Dr McEwan a grant, said the project could save lives.
A&E consultant Martin Shalley, president of the British Association for Emergency Medicine, said: "The quicker you can make the diagnosis the better. This sounds like it has great potential.
"Even if a diagnosis could not be made, just having the scan ready when the patient arrives at hospital would be a big step.
"Arranging a hospital scan can lose you valuable time."
The Stroke Association called the project "promising".
A spokeswoman added: "Any technology that could rapidly identify the cause of a stroke could potentially have hugely beneficial effects."