The time it takes to identify a stroke and transport a stroke victim to the hospital to be diagnosed can shape the rest of a person's life, researchers say.
To accelerate critical diagnosis time, Swedish researchers are developing a new medical instrument, Strokefinder, which will enable paramedics to diagnose strokes right from the ambulance.
Strokefinder is a helmet-shaped tool that transmits weak microwave signals into the brain to diagnose whether the stroke is a bleeding stroke or a clot-induced stroke. The difference is important, said Mikael Elam, Strokefinder project leader and professor of clinical neurophysiology at Sahlgrenska University Hospital in Sweden. The blood-thinning treatment given to victims of a clot-induced stroke to dissolve the blood clots could prove fatal if the victim was suffering a bleeding stroke.
Elam collaborated with a team of researchers at the Chalmers University of Technology in Sweden, led by Mikael Persson, a professor of biomedical engineering. Over the course of 10 years the researchers have been testing how microwaves penetrate the brain, and developing Strokefinder to use that technology to diagnose strokes. The researchers conducted a study with 45 patients, recently published in the IEEE Transactions on Biomedical Engineering journal, which showed Strokefinder could differentiate clearly between bleeding strokes and clot-induced strokes.
"The possibility to rule out bleeding already in the ambulance is a major achievement that will be of great benefit in acute stroke care," Persson said. "Equally exciting is the potential application in trauma care."
Strokes are caused when blood flow is cut off to the brain, resulting in millions of brain cells dying due to oxygen deprivation, said Andrei Alexandrov, a neurologist and professor at University of Tennessee. This can lead to permanent disability if the stroke is not diagnosed and treated within the first few hours. Strokes are the leading cause of permanent disability in adults, and this is often because the symptoms aren't recognized right away and, unlike with a heart attack, there is no pain, Alexandrov said.
"The problem with strokes is that symptoms can be so diverse and discreet," Elam said.
Stroke victims should be taken to the hospital within the first hour, Alexandrov said, because hospitals can take some time to identify the symptoms and do a CT scan to identify the type of stroke. If the victim has a clot-induced stroke and is given the clot-dissolving medicine within two hours, the chance of that person fully recovering doubles, Alexandrov said. This type of stroke strikes 85% of the stroke victims in the western world, according to Elam.
"What you do during the first hour will largely determine the rest of your life," Alexandrov said.
Elam and Persson hope that diagnosing stroke victims from the ambulance with Strokefinder can double the number of patients who reach a diagnosis in that critical time before the brain loses too much oxygen. About 2% to 8% of stroke victims actually get the needed diagnosis before any permanent damage takes place, Elam said.
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Strokefinder helmet can diagnose strokes from ambulance