Portable MRI System Dramatically Cuts Time-To-Scan vs. Conventional MRI in Stroke Patients

Imaging of the brain is crucial for the management of acute stroke and transient ischemic attack. Key roles of imaging include confirming the diagnosis, determining treatment eligibility, indicating the probable mechanism, informing prognosis, and identifying complications related to stroke or its treatment. Magnetic Resonance Imaging (MRI), especially the Diffusion Weighted Imaging (DWI) sequence, is particularly well-suited for this purpose as it is highly sensitive to changes in brain water distribution that may not be easily visualized on X-ray-based computed tomography (CT) during the initial hours after the onset of ischemia. However, access to MRI can be limited due to several factors, including the necessity for patient compatibility checks for metal implants or devices that are not compatible with the strong magnetic fields used in standard clinical MRI, challenges in monitoring critically ill patients within the MRI scanner, and the discomfort caused by the confined space, which may induce claustrophobia and lead to non-diagnostic images, as image acquisition typically takes 15-30 minutes for a complete examination. Now, interim results from a new study support the potential role of portable ultra-low-field MRI in the acute stroke assessment process within a hospital emergency department.

This prospective observational study conducted by researchers at the University of Glasgow (Scotland, UK) explored the potential benefits of mobile MRI for patients with suspected or confirmed acute stroke and transient ischemic attack. The study involved additional imaging in the emergency department and a comparison of diagnostic accuracy and DWI lesion volume. Researchers utilized Hyperfine’s (Guilford, CT, USA) Swoop portable ultra-low-field MRI scanner, designed to provide neuroimaging at the patient’s bedside. The Swoop system has received U.S. Food and Drug Administration (FDA) clearance for brain imaging across all age groups, producing images that reveal the internal structure of the head where a full diagnostic examination is not clinically practical. When interpreted by a trained physician, these images can yield valuable information for diagnosis.

This study includes a subset of patients from phase one of the prospective, international, multi-site ACTION PMR (Acute Ischemic Stroke Detection with Portable MR) study and analyzed images obtained from the ultra-low-field Swoop MRI brain imaging system to evaluate its performance in the acute care stroke workup compared to the current standard of care. The analysis assessed time-to-scan, diagnostic performance, specificity, and patient experience across ultra-low-field MRI, conventional MRI, and head CT. Key findings indicated that the Swoop system was significantly faster than conventional MRI, with a median time-to-scan of 2.5 hours compared to 27.7 hours. The data also demonstrated that the Swoop system reliably diagnosed acute strokes, showing comparable diagnostic performance to head CT and good specificity when compared to routine clinical MRI (1.5T). Furthermore, nearly all patients reported a positive experience with the Swoop system.

“This interim analysis demonstrates that the portable [ultra-low-field] MRI system is a promising tool for the acute stroke diagnostic workup in an emergency department setting. The improved time to imaging compared to routine MRI could facilitate quicker decision-making in acute stroke management. Additionally, the high tolerance rate among patients underscores its potential usability in a clinical environment. The findings suggest that portable [ultra-low-field] MRI could enhance stroke diagnosis accessibility and efficiency, particularly in settings where conventional MRI availability is limited,” concluded the report.

Related Links:
University of Glasgow
Hyperfine