Portable MRI may provide more accessible images for stroke survivors

Magnetic resonance imaging (MRI) technology is a mainstay of modern medicine — at least, for those who have access to it. Field MRI scanners can now provide more detailed images of the brain than ever before, yet they remain elusive in many parts of the world.

However, less powerful and less resource-intensive MRI may give more people access to life-saving imaging resources. According to a new study published in the April 22 issue of science progressNeurological images were acquired using a portable pMRI device with very low magnetic field strength. Areas of dead tissue were detected in the brains of 50 stroke patients.

Doctors reviewed treatment plans for two COVID-19 intensive care patients based on stroke damage detected by pMRI. The findings support the idea that low-field fMRI may provide a clinically viable technology for stroke patients and could help democratize access to biomedical equipment in resource-scarce settings.

“MRI is a cornerstone of stroke evaluation, but there is limited access to conventional high-field MRI due to size, cost, and safety considerations,” said W. Taylor Kimberly, chief of neurological care at Massachusetts General Hospital. D., associate professor of neuroscience at Harvard Medical School, and co-author of the study. “Mobile MRI brings imaging technology to the patient’s bedside, and has the potential to expand access due to its low cost and portability.”

expand access

Field MRI machines, which use radio waves to create detailed deliveries of organs and tissues, have grown in strength since they were first approved in the mid-1980s. But for this imaging technology, with great power comes the large production expenses, the consumption of refrigerant (used to cool the magnet), the needs of specialized personnel and the use of electric power. Many low- and middle-income countries do not have the resources to support conventional MRI machines. Even basic radiology services, such as x-rays, are in short supply in many states. According to the World Health Organization, an estimated two-thirds of the world’s population does not have adequate access to these services. There are also differences between radiologists who read imaging tests. 2016 article in Atlantic Ocean He points to one hospital in Boston that has 126 radiologists while the whole of Liberia has only two.

Even the wealth of imaging technologies in the United States is concentrated in urban areas, leaving segments of the population without access to radiology services. Stroke centers, for example, are usually located in densely populated areas of the country. When someone in a rural community has a stroke, they may need to be flown by helicopter to the center.

“When we started working on portable MRI, we thought about potential clinical use case scenarios,” Kimberly said. “While we had a number of ideas, we became more and more excited about the possibility of using portable MRI for stroke diagnosis and monitoring, an area where repeat imaging is commonly needed for management decisions.”

Added Kevin Sheth, MD, professor of neurology and neurosurgery at Yale University School of Medicine, and vice president for clinical and multidisciplinary research in the departments of neurology and neurosurgery. “Several groups have been working on the physics and engineering principles behind low magnetic field-based imaging for years. In recent years, this work has moved into the clinical setting. Our group has been privileged to be the first in the world to deploy such a device in a clinical setting, and this paper is one From several papers we have published.

Detecting damage in a stroke

Previously, researchers demonstrated that low-field functional magnetic resonance imaging can be used to assess and monitor brain injury from hemorrhagic strokes caused by bleeding in the brain. However, there have been few evaluations of how this technique performs with strokes caused by reduced blood flow, which account for 87% of all strokes.

To investigate how pMRI technology performs with this common type of stroke, Matthew Yuen, MD. A candidate at Yale University School of Medicine and first author of the study, and colleagues used low-field functional magnetic resonance imaging to obtain intracranial bedside imaging of 50 stroke patients in a hospital emergency department, inpatient neuroscience intensive care unit, and intensified COVID-19 care unit. The pMRI machine, which Sheth described as “slightly shorter than the average adult and as wide as a standard entrance,” is controlled by an iPad and uses magnets with less than 1% of the strength of those in the largest clinical units.

For 90% of patients, MRI was successful in identifying dead tissue in affected areas of the brain, which was also imaged using standard-of-care neuroimaging. Two COVID-19 intensive care patients who could not be transferred to sites using conventional non-contrast computed tomography (NCCT) or MRI were imaged by MRI in hospital beds. The technology revealed the harm caused by unknown strokes in these patients, eventually leading to adjustments in patients’ treatment plans after results were confirmed by conventional neuroimaging. The results demonstrate the usefulness of this relatively weak MRI for assessing stroke damage in intensive care settings.

“We were pleased to see that we could detect strikes of different sizes at different points in time,” Sheth said. “At the same time, while our ability to detect stroke is very good, it is clear that much work needs to be done in order to use the device in routine clinical practice.”

“The cost of the device will need to be further reduced for a large number of patients and providers to be able to use it, and greater understanding of the clinical workflow and personnel required to use the device will be required,” he added. “There will also be a need to develop and openly share very large data sets, gathering them from a variety of settings, so that the medical and scientific community can have confidence in the correctness of the image interpretation.”

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