“Stroke is a time-sensitive disease,” says Kevin Sheth, MD, a critical care neurologist at Yale Medicine. After the onset of a stroke, every minute and treatment decision can not only make the difference between life and death, but also long-term disability.
A stroke occurs when normal blood flow in the brain is interrupted. Ischemic strokes (87% of all strokes) are those that happen when a blood vessel is blocked, while hemorrhagic strokes occur when a blood vessel ruptures. The symptoms for both look the same, but the treatments are different. So being able to identify which type of stroke a patient has had is vital: “With every passing minute, millions of neurons are dying, and there are also time-sensitive therapies,” explains Dr. Sheth.
The technology that lets doctors see inside the brain to make the right diagnosis is MRI (magnetic resonance imaging), and it has been available for decades. Doctors use MRI to obtain critical diagnostic information about a stroke—including the type, size and location of it. And unlike other types of medical imaging, there is no radiation involved.
But, until now, there have been logistical challenges making it difficult for doctors to get the information they need quickly. MRIs use powerful magnets to create their detailed images, technology that has required these machines to be in a bunker-type room, often in the basements of hospitals. Their size and cost mean they can’t be placed in outpatient clinics. As a result, stroke patients often don’t get a scan as quickly as they should after arriving at the emergency department; some end up waiting up to an hour. “What you’d love to do is be able to use an MRI and take pictures over and over again,” says Dr. Sheth.
Dr. Sheth collaborated with a group of doctors and engineers from Connecticut-based company Hyperfine Research to develop and test a portable MRI machine—one that does not require the same type of high-field magnets used in a conventional MRI, allowing it to be safely operated in any room. “The fundamental gap there was the development of something called ‘low field.’ Is there a way you can generate these images using a much lower field?” Dr. Sheth says. “It's a paradigm shift—from taking a sick patient to the MRI to taking an MRI to a sick patient.”
Since receiving a prototype of the portable MRI from Hyperfine, Dr. Sheth and his colleagues have captured images from over 100 stroke patients. Dr. Sheth foresees a future where portable MRIs could be set up in the backs of ambulances and clinic rooms, making a powerful diagnostic tool available to far more stroke patients at a fraction of the cost and time of a conventional MRI. “Now that you’re able to do this,” he says, “you start to think—what’s the limit to this?”