The Road Ahead?
By Beth W. Orenstein
Radiology Today
Vol. 25 No. 7 P. 14
Portable scanners expand research opportunities while raising legal and ethical questions.
Over the past half-century, MRI has transformed neuroscience research. Because MRI scanners are expensive and require significant infrastructure, most of this research has been done in hospitals and large research institutions. Due to their large size and weight, it is difficult to set up MRI machines in remote or resource-limited areas. As a result, MRI is primarily available in wealthier countries.
The recent advent of highly portable MRI machines promises to change this paradigm and add greater detail to studies of the brain. Highly portable scanners can go “almost anywhere [to image] almost anyone,” says Michael Garwood, PhD, a physicist and associate director of the Center for Magnetic Resonance Research at the University of Minnesota in Minneapolis. Researchers at the center are working on a compact 0.7 T MRI system that can fit on the back of a pickup truck and operate with a generator that could be bought in a hardware store. The portability of such MRI scanners opens a world of possibilities, Garwood says.
Additionally, in the last few years, Hyperfine Inc, a medical technology company based in Guilford, Connecticut, has developed a portable MRI machine, the Swoop system, which has been FDAcleared for several applications, including the assessment of brain health and injury in patients of all ages. The Swoop magnet has a field strength of 0.064 T and can be transported to a patient’s bedside through standard doorways. It plugs into a standard electrical wall outlet and is controlled through an Apple iPad Pro.
Edmond Knopp, MD, vice president of medical affairs at Hyperfine, Inc, says portable MRI such as the Swoop system not only expands MRI’s utility for neuroimaging research but also improves patient care and reduces cost. The Swoop system, he says, is ideal for pointof- care imaging in intensive care units, pediatric facilities, and other health care settings.
“By bringing diagnostic MR imaging to the point of care, a Swoop system may potentially prevent adverse events related to transport and reduce patient care interruptions,” Knopp says.
The Swoop system may also help reduce the length of stay (and associated costs) in the ICU by enabling clinical care teams to potentially optimize staffing, expedite and improve patient care, and shorten the time to diagnosis. “Point-of-care MR imaging can take as little as 0.5 to 5.3 hours, from ordering the scan until the images are available for assessment—a significant time reduction from the 11.7 hours it takes for conventional high-field MR imaging of critical patients,” Knopp says.
Stroke Imaging
The Swoop system reduces potential adverse events associated with patient transport and brings neuroimaging to the bedside of critically ill patients who are too unstable for transport to radiology. It complies with electromagnetic compatibility emission standards and is not expected to affect most ICU equipment. “Because of this, patients can remain connected to all intravenous lines and most ICU monitoring equipment, as long as [the monitoring equipment] remains outside the 62-inch diameter-controlled access area,” Knopp says. Knopp says the Swoop system also helps optimize scheduling and increases staff efficiency by reducing the time required to coordinate patient transport to radiology while allowing ICU staff to remain in the ICU at the patient’s bedside or available to assist other patients.
Brain imaging is crucial to the successful management of patients who suffer a stroke. However, imaging critically ill patients with stroke can be challenging because transporting patients to radiology for a CT scan or to MRI suites has risks. Portable MRI allows patients to be imaged at their bedside, and positive findings can allow for life-saving treatment to begin as soon as possible. Knopp believes portable MRI can help in these scenarios.
A study published in August 2021 in the journal Nature Communications found that the Swoop portable MRI system could help correctly identify intracranial hemorrhages in areas or scenarios where access to more sophisticated brain imaging, such as CT or conventional MRI, is not readily available. The study was conducted at Yale New Haven Hospital from July 2018 to November 2020. Two board-certified neurologists interpreting the images acquired by the portable MRI correctly identified 80% of intracerebral hemorrhages. The study was the first to validate the appearance and clinical implications of brain hemorrhage using a portable MRI device, Knopp says.
Another study published in April 2022 in ScienceAdvances found that low-field portable MRI could be used to obtain actionable bedside neuroimaging for patients with ischemic stroke. It was used to obtain bedside intracranial imaging for 50 patients with ischemic stroke. About half of the patients were female and had a median age of 61. The researchers found that the 0.064 T portable scanner, used in inpatient and emergency department settings, accurately demonstrated and characterized ischemic stroke at bedside. In addition, they found that portable MRI could be used to monitor patients with ischemic stroke.
Evaluating Mobility
While the Swoop system has not been cleared for use in vehicles and is only indicated for use in professional health care settings, some researchers are exploring the viability and potential of MRI systems in mobile settings, such as ambulances. Researchers at Clemson University and the Medical University of South Carolina published a study in June 2024 in Ergonomics that looked at integrating portable MRI systems into ambulance services so patients could be triaged before they arrived at the emergency department, potentially reducing door-to-needle time for thrombolytic administration. The goal of the study was to look at the challenges of performing MRI using portable scanners en route.
Kapil Chalil Madathil, PhD, a Clemson University professor of industrial and civil engineering and one of the authors, states that there are several significant barriers to MRI use in ambulances. These include challenges in making triage decisions during patient transit, physical constraints due to the size and weight of portable MRI devices, space limitations that complicate integration, difficulties in establishing standard operating procedures, inadequate paramedic training in MRI operation for stroke diagnosis, potentially compromised image quality due to scanner instability in moving vehicles, maintenance challenges for MRI devices in vehicles, airway management issues affecting stroke care, and staffing and scheduling challenges.
Paramedics expressed concerns about the cognitive demands required to identify ferromagnetic objects on a patient’s body to ensure safety around the MRI’s magnetic field. They also expressed concerns about the confined headspace for a patient in the MRI device and how it could be uncomfortable for those with claustrophobia. If patients were in discomfort, they may not remain still for optimal imaging, the researchers found. Paramedics and neurologists also expressed concerns about the lack of coordination between the emergency ambulance personnel and the teams at the destination hospital. Other concerns included challenges accessing patient history for MRI use in ambulances and producing diagnostic quality MRI images due to scanner instability in a moving ambulance.
Still, Chalil Madathil says he believes that all the issues that were identified could be resolved by taking a systems approach rather than focusing solely on the most difficult or easiest problems. “The study recommends this comprehensive systems approach to address the barriers effectively,” he says. Chalil Madathil believes it’s worth finding solutions to the concerns that were raised because “Using portable MRI systems in ambulances would allow health care providers to make faster diagnoses and early interventions before patients arrive at the hospital. This capability means ambulances could bypass nearby rural hospitals for brain scans and go directly to a stroke center.” Chalil Madathil is confident that solutions will be found and that portable MRI scans of suspected stroke patients en route to emergency departments “is the future.”
Slow and Steady
Garwood says he and colleagues at the University of Minnesota have built their portable MRI, which has a magnet that is 10 times stronger than the Swoop system’s, but, as of this summer, have not used it to test a human subject. “We need to assure the system is safe before we do that,” he says. The team also is waiting for additional grant money from the National Institutes of Health. “We are seeking a five-year grant that will help us get through the approval process and allow us to see what the image quality is like on normal subjects,” Garwood says.
Garwood is optimistic that his group’s 0.7 T portable MRI will produce quality images that will be extremely helpful in taking MRI on the road and including patients in studies who normally would not be able to participate because they couldn’t access conventional MRI. He says machine learning and AI will help improve image quality of low-field magnets such as the Swoop system, but he doesn’t want to depend on these approaches. “We might want to use AI in the future to enhance image quality,” Garwood says, “but you don’t want to rely on it so heavily that the image shows something that is not really there.”
Garwood says his group is “a lot slower” than Hyperfine, Inc, in developing their portable MRI because they work for an academic institution. However, he says, their portable MRI is lighter, even though its magnet is 10 times the strength of the Swoop system’s.
Ethical, Legal, and Policy Challenges
While highly portable MRI is set to transform neuroscience research, a number of legal and bioethics scholars worry that its development presents ethical, legal, and policy challenges, especially in communities that have not previously participated in brain research. To head off this dilemma, a national working group led by three University of Minnesota professors has published a new report in the Journal of Law and the Biosciences that, they say, provides “urgently needed guidance” on the “rapidly emerging use of portable MRI for brain research.”
The report was funded by a $1.6 million four-year grant from the National Institutes of Health BRAIN Initiative, which is why it focuses on brain research, says one of the three lead professors, Francis X. Shen, JD, PhD. However, he says, the issues it raises could apply to all uses of portable MRI. “Some of our 15 recommendations are particularly relevant to the brain,” Shen says, “but other recommendations would be applicable to an MRI of the knee or foot or whole body.”
Garwood also served on the committee that wrote the report and recommendations.
The report “Ethical, Legal, and Policy Challenges in Field-Based Neuroimaging Research Using Emerging Portable MRI Technologies: Guidance for Investigators and for Oversight” contains 15 recommendations. Among the key recommendations are:
• New guidelines and training are needed for the safe use of portable MRI in field settings. The guidelines should include robust standards for participant privacy and data security.
• When using AI with portable MRI to generate images and interpret the meaning of those images, participants should be informed and asked to consent. The meaning of the AIgenerated images should be carefully evaluated.
• While the emergence of citizen scientists using portable MRI technology will advance the study of neuroscience in new and exciting ways, it also will require safeguards, such as those now provided by traditional institutional review and oversight.
• Questions need to be answered about how to convey incidental findings from portable MRI to participants who may not have health insurance or who don’t live near medical facilities that would give them access to the clinical evaluation and treatment they may need.
• Because portable MRI scanners will enable new research partnerships with previously underrepresented communities in remote locations, investigators designing the research projects should partner with the local communities where the research will occur.
Shen believes that “With sufficient guardrails, portable MRI can live up to its promise.”
— Beth W. Orenstein of Northampton, Pennsylvania, is a freelance medical writer and regular contributor to Radiology Today.
