International Study Focused on Defining a New Imaging Paradigm in Stroke Care—A Response to the Urgent Need for Improved Ischemic Stroke Diagnosis and Treatment

Hyperfine, Inc. recently announced the commencement of a prospective, international, multi-site observational study called ACTION PMR (ACuTe Ischemic strOke detectioN with Portable MR). This study aims to examine the integration of brain imaging with the Swoop® system into the stroke diagnosis and treatment workflow. The goal is to use point-of-care brain imaging to identify strokes and viable brain tissue that can be saved.

Addressing the Pressing Health Challenge of Stroke

In the US, the prevalence of stroke survivors, those living with stroke-related disabilities, and stroke-related deaths has steadily increased since 19901. Stroke affects over 795,000 Americans annually, marking it a leading cause of severe long-term disability2. The majority of these cases, about 87%, are ischemic strokes, which is when blood flow to the brain is obstructed1. This illness significantly affects mobility in over half of stroke survivors aged 65 and over1. Economic repercussions are significant, with stroke-related costs in the US reaching nearly $56.5 billion between 2018 and 20191.

When a stroke occurs, a small group of cells experience a complete loss of blood supply and die within minutes, while a larger region with more moderate blood flow reduction can survive longer. Acute ischemic stroke therapy aims to save this "penumbra," the area of initially ailing but still salvageable tissue. Reperfusion before the infarct growth is complete can salvage the residual penumbra and reduce the final infarct size3.

Multimodal imaging with CT or MRI facilitates the rapid identification of infarcted brain regions and regions that are still salvageable4. MRI has proven more precise than CT and is endorsed by the American Academy of Neuroradiology for diagnosing acute ischemic stroke within twelve hours of symptom onset5. A significant challenge is that many hospitals do not have an MRI near their critical care units, and transporting patients to MRI suites can introduce delays or adverse event risks6. Therefore, addressing the lack of available brain tissue imaging options through alternative solutions, such as point-of-care MR brain imaging, could significantly enhance stroke care, thereby reducing disability, improving patient outcomes, and potentially saving more lives.

“The ACTION PMR observational study has the potential to improve stroke treatment all over the world, with the Swoop system assisting clinicians in imaging brain tissue and making timely diagnoses, which could lead to the implementation of more effective treatments and help to facilitate better patient outcomes,” says Dr. Khan Siddiqui, Hyperfine, Inc. Chief Medical Officer and Chief Strategy Officer.

The ACTION PMR Observational Study: A Step Towards Better Stroke Care

As stroke treatment best practices continue to evolve, timely intervention remains a critical factor. Delay in stroke treatment can lead to severe consequences, including neurological, cognitive, and physical disability or death. The length of time of the blockage directly influences the degree of damage sustained, highlighting the necessity for immediate medical help at the onset of signs and symptoms. The potential for point-of-care brain imaging with the Swoop system to have a tremendous impact on these scenarios offers hope for timely, more efficient interventions that could change the course of stroke treatment.

Hyperfine, Inc. is launching the ACTION PMR observational study as a prospective, international, multi-site observational study working exclusively with adult emergency department patients with signs of acute ischemic stroke in the late window. The study aims to assess the Swoop system’s feasibility and validate its claims regarding the visualization of acute ischemic infarcts and the identification of viable brain tissue.

The ACTION PMR observational study will focus on patients experiencing a stroke during sleep or presenting in the late-window period of six to twenty-four hours from the last known time the patient was well, a population traditionally underserved in current medical practice. This research will also explore the viability of intravenous thrombolysis for patients presenting with a mismatch between a visible lesion on DWI and normal FLAIR (referred to as DWI–FLAIR mismatch), potentially indicating salvageable brain tissue for reperfusion.

The point-of-care Swoop brain imaging system will be central to the ACTION PMR observational study. The potential benefits of the Swoop system are many—enabling the identification of salvageable brain tissue, facilitating earlier intervention strategies, and paving the way to save more lives. The study will test the system’s feasibility, sensitivity, and specificity in the late-window stroke context relative to standard-of-care neuroimaging by correlating the last seen well time ("time clock") and T2-weighted FLAIR intensity ("tissue clock").

The study represents a tremendous potential stride in transforming stroke care globally. As a company at the forefront of medical device innovation, Hyperfine, Inc. is committed to significantly enhancing stroke diagnosis and treatment, particularly for patients within the traditionally underserved 'late window' period. The Swoop system holds the potential to revolutionize stroke care, offering the opportunity for quicker diagnosis, more effective interventions, and ultimately improved patient outcomes. This study is not just about challenging the norms but shifting them entirely to save more lives and decrease the devastating impact of strokes. The ACTION PMR observational study and the Swoop system stand as testaments to the commitment of Hyperfine, Inc. to pioneering change and progress within the realm of stroke care, epitomizing the company's ethos of healthcare innovation designed to benefit those who need it the most.

Four investigators from leading institutions will lead the study: Dr. W. Taylor Kimberly of Massachusetts General Hospital, Dr. Adnan Siddiqui of the University at Buffalo, Dr. Vivien Lee of the Ohio State University Wexner Medical Center, and Dr. Keith Muir of the University of Glasgow.

“Refining stroke diagnosis and care is central to all we do; as such, our research will focus on patients who don’t immediately qualify for thrombectomy,” says Dr. Taylor Kimberly of Massachusetts General Hospital. “We hope this study may contribute to timelier diagnoses, paving the way for improved patient outcomes.”

Maria Sainz, Hyperfine, Inc. President and CEO, adds, "There is a significant unmet need in stroke imaging and workflow representing a very compelling incremental opportunity for Hyperfine, Inc. Our ambition is to enable innovative and readily accessible brain imaging solutions that enhance the chances of recovery for every patient. The ACTION PMR observational study is an important project for us, and we are honored to be working with our distinguished clinical investigators and stroke advisors to navigate the challenges and opportunities in stroke care and formulate the role the Swoop system can play in acute stroke workflow.”

We invite you to explore our website to learn more about the benefits of the Hyperfine, Inc. Swoop® Portable MR Imaging® system.



1. American Heart Association News. “U.S. Stroke Rate Declining in Adults 75 and Older, Yet Rising in Adults 49 and Younger.” American Heart Association, 9 Feb. 2023, https://newsroom.heart.org/news/u-s-stroke-rate-declining-in-adults-75-and-older-yet-rising-in-adults-49-and-younger. Accessed 13 June 2023.

2. Tsao, Connie W et al. “Heart Disease and Stroke Statistics-2023 Update: A Report From the American Heart Association.” Circulation vol. 147,8 (2023): e93-e621. doi:10.1161/CIR.0000000000001123

3. Jeffrey L. Saver, MD, “Penumbral salvage and thrombolysis outcome: a drop of brain, a week of life, Brain.” Volume 140, Issue 3, March 2017, Pages 519–522, doi:10.1093/brain/awx020

4. Campbell, Bruce C V et al. “Comparison of computed tomography perfusion and magnetic resonance imaging perfusion-diffusion mismatch in ischemic stroke.” Stroke vol. 43,10 (2012): 2648-53. doi:10.1161/STROKEAHA.112.660548

5. Schellinger, P D et al. “Evidence-based guideline: The role of diffusion and perfusion MRI for the diagnosis of acute ischemic stroke: report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology.” Neurology vol. 75,2 (2010): 177-85. doi:10.1212/WNL.0b013e3181e7c9dd

6. Barbara McLean, Douglas Thompson, “MRI and the Critical Care Patient: Clinical, Operational, and Financial Challenges.” Critical Care Research and Practice vol. 2023, Article ID 2772181, 8 pages, 2023. doi.org:10.1155/2023/2772181

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