Brain scanning method improves outcomes for emergency stroke patients

A trial conducted at 38 U.S. medical centers shows that a brain scanning method—called perfusion imaging—is able to help identify more patients who are eligible for emergency stroke treatment later than was previously considered possible.

Thrombectomy, the physical removal of a blood vessel blockage in the brain, had been previously recommended for eligible patients with acute ischemic stroke who are treated within six hours after the onset of symptoms.

However, using an automated software package called RAPID developed by iSchemaView to analyze perfusion MRI or CT scans, researchers identified patients thought to have salvageable tissue up to 16 hours after stroke onset.

“Half of all patients treated between six and 16 hours after the onset of their symptoms had a complete, or nearly complete, recovery from their stroke,” said Gregory Albers, MD, professor of neurology and neurological sciences at Stanford University School of Medicine, director of the Stanford Stroke Center, and the trial’s principal investigator.

Results of the Endovascular Therapy Following Imaging Evaluation for the Ischemic Stroke (DEFUSE 3) trial were presented on Wednesday by Albers at the International Stroke Conference 2018 in Los Angeles and were also published in the New England Journal of Medicine.

“The software provided by iSchemaView was a critical element to the success of the DEFUSE 3 study,” Albers added. “Previous studies indicated that treatment benefit was lost after 6 or 7 hours, but the RAPID software was able to identify a large group of patients who had substantial benefits even if treated more than 12 hours after the onset of stroke symptoms.”

RAPID, initially validated in the DEFUSE 2 study published in 2012 and cleared by the FDA in 2013, was developed to provide accurate and reliable perfusion and diffusion imaging processing that could be performed on any CT or MRI scanner.

Albers co-developed the software and holds equity in iSchemaView, based in Redwood City, Calif., that has licensed it from Stanford's Office of Technology Licensing. He is also a consultant for iSchemaView, which supplied the software used in the trial.

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“These striking results will have an immediate impact and save people from life-long disability or death,” said Walter Koroshetz, MD, director of the National Institute of Neurological Disorders and Stroke, which funded the study. “I really cannot overstate the size of this effect. The study shows that one out of three stroke patients who present with at-risk brain tissue on their scans improve and some may walk out of the hospital saved from what would otherwise have been a devastating brain injury.”

Not surprisingly, the American Heart Association/American Stroke Association on Wednesday issued new guidelines for the early management of patients with acute ischemic stroke, recommending that more people should be considered to undergo thrombectomy. In addition, the guidelines suggest that more people should be considered eligible for a clot-dissolving IV medication called alteplase.

“This is going to make a huge, huge difference in stroke care,” said William Powers, MD, guidelines writing group chair and chair of neurology at the University of North Carolina School of Medicine in Chapel Hill.