Portable LF MRI Can Improve Access and Diagnosis of Acute Ischemic Stroke

Nandor Pinter, MD, research assistant professor at the Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo, presented a prospective study that scanned patients presenting to the emergency department across three U.S. stroke centers and determined the agreement and predictive values of accurately detecting stroke.

Portable MR Can Impact Stroke Care

In total, 66 patients were enrolled in the ACTION PMR (ACuTe Ischemic strOke detectioN with Portable MR) study from Massachusetts General Brigham, Buffalo General Medical Center and Ohio State Hospitals and underwent diffusion weighted imaging (DWI) on the Swoop® portable MR imaging system from Hyperfine, a LF MRI system that is portable, lightweight and can be used in the Emergency Department with a standard power outlet.

Three independent assessors, each with more than ten years of experience reading acute stroke MRI were trained on LF MRI images and then evaluated the scans. The study found strong agreement between assessors regarding lesion detection and lesion location and favorable positive predictive values for detecting AIS. Sources of disagreement were observed when lesions were smaller and less conspicuous.

“It is always exciting to test new technologies in practice, especially in an important clinical area such as acute stroke, where portable MRI can make a difference,” Dr. Pinter said. “The field of portable MRI has been developing dynamically in recent years, and acute stroke care is among the most important areas where it can be utilized.”

Dr. Pinter said the clinical implications could vary but could have a real impact on stroke care for many. 

“For example, a stroke center where CTA is routinely done, may choose to use a portable MRI only in CT negative cases, to distinguish strokes from stroke mimics,” Dr. Pinter said. “While in other practice settings the system may serve as a triage role. In wake-up strokes, in particular, the diffusion-weighted MRI (DWI) and fluid-attenuated inversion recovery (FLAIR) MRI mismatch obtained with LF MRI could be used as a tissue clock to guide decisions about thrombolysis. The portability and safety profile make all of this possible with LF MRI. Instead of transporting patients to an MRI suite, the scan is done at the bedside, saving precious time.”  

He referenced results presented by Dr. Keith Muir from University of Glasgow at this year’s annual meeting of European Society of Neuroradiology, that showed that time-to-scan was dramatically reduced with the portable MRI system, with a median time-to-scan of 2.5 hours compared to 27.7 hours on conventional MRI. In the ACTION PMR study, Dr. Pinter said the wait time for traditional MRI was 14 hours longer than LF MRI.

He said he hopes there are more trials in the future that combine the strengths of clinical radiologists, radiological societies, and vendors and explore the use of LF MRI for conditions including TIAs and larger strokes.

“As with every new technology, we need to understand its strengths and limitations, or how it fits in the workflow best, before clinical implementation,” Dr. Pinter concluded. 

Access the presentation, “Acute Stroke Detection Using Portable Ultra Low-Field MRI: A Multicenter Outlook,” (M3-SSNR04-2) on demand at RSNA.org/MeetingCentral