Brain Imagers Gear Up as a New Era Dawns for Stroke Care

Medical historians may one day look back on 2018 as the year having a stroke stopped bringing an inescapably bleak prognosis to victims who went a while before noticing the symptoms. 

The spurring event was the changing of guidelines from the American Heart Association and American Stroke Association. For years, the groups’ joint guidelines allowed only a six-hour window after onset for interventionalists to pull clots or masses blocking the flow of blood to the brain in ischemic strokes, as nearly 90 percent are. The aim of such removal is to preserve brain tissue that is at risk but still alive. 

Now, following the publication of two definitive stroke studies in the New England Journal of Medicine—DAWN in January and DEFUSE-3 in February—the groups have opened the clot-removal window to 24 hours for many of these patients.

This is a big deal. According to the CDC, someone in the U.S. has a stroke every 40 seconds. Around 140,000 people die of stroke each year: about one victim every four minutes. And more than half of those aged 65 and older who survive a stroke suffer long-term losses in mobility. 

The new guidelines continue to focus the initial steps on basic head CT images that should be acquired within 20 minutes. If this exam confirms stroke, and if the radiologist finds no contraindications for a clot-busting drug, the patient should receive an infusion of tPA. (Common contraindications include tumors, seizures and aneurisms.) 

It’s the more forceful and decisive next step—mechanical thrombectomy with stents and/or other devices—that will now be taken for patients whose strokes have been underway for up to a full day, saving many more lives and preserving quality of life on a much broader scale. 

“We have more time to aggressively treat stroke than we thought we had in the past,” says J.P. Dym, MD, director of the stroke imaging program at vRad, the Minnesota-based teleradiology practice that maintains a team of over 70 neuroradiologists for 24/7 coverage. “My hope and my expectation is that the tide in the fight against stroke is going to change now.”

The development is consequential enough that Dym and colleagues have scheduled a free webinar to flesh out its details on June 28. More on that later. 

“When stroke patients don’t do well, they really don’t do well,” Dym underscores. “A patient with a stroke caught late needs lots of resources and faces a long, hard rehab. These events have a significant effect not only on patients and their families but also on the healthcare system.”

Indeed, the CDC estimates stroke costs U.S. healthcare close to $34 billion per year. 

Time is Still Brain  

The extension to 24 hours for aggressive treatment of stroke has especially powerful ramifications for cases in which the time of onset is unknown. Research has shown that at least 25 percent of strokes are underway when the patient wakes from sleep. Did the stroke start shortly after slumber began, just before wakeup or somewhere in the middle? With “wakeup stroke,” there’s no way to tell. 

“This can be a crazy source of frustration for patients, family members, physicians—everyone involved,” Dym says. “Now, he or she is automatically a candidate for the gold-standard intervention.”

Dym has one concern over the extended treatment window. It has to do with mindset. 

“I hear some hospitals are feeling there’s less of a rush now,” he says. “I hope nobody in stroke care loses sight of the fact that time is still brain. And the primary rescuer of brain from stroke is still a non-contrast head CT.”

From that initial test, it’s critical for the radiologist to get word to the attending ER physician nearly instantly so they can administer tPA if appropriate. “The main point is that you have to be looking for blood right away,” Dym adds. For that reason, vRad has a standing recommendation that ERs separate and transmit the head CT even if the patient simultaneously received high-level scanning. 

“Sometimes they do the head CT plus CT angiography (CTA) or CT perfusion in quick succession, while the patient is on the table,” he says. “A lot of times they image the neck for the carotid artery as well. Everything-at-once image acquisition makes sense, but that head CT image data has to be separated out and read—with at least a verbal or preliminary report going to the treating doctor—as quickly as possible.” 

Speed, Accuracy & Care Continuity 

The more advanced imaging options, which also include brain MRI, show various details crucial to saving brain tissue at risk, Dym explains. 

CTA can show the interpreter small vessel occlusions or, for another example, a thrombus blocking one of the main blood vessels that the interventionalist can go after. “The CTAs we’re seeing today are just gorgeous,” Dym says. “It’s basically like looking at a catheter angiogram.” He notes that vRad ensures punctuality with a dedicated system, “Call on Open,” which automatically phones the referrer seven minutes after the radiologist opens the CTA study if he or she hasn’t manually done so by then.

CT perfusion is a powerful tool for enabling the radiologist to differentiate between ischemic brain tissue that is still salvageable and tissue that is past the point of no return. From this insight the interventionalist can more confidently identify the most efficacious care path, Dym says. 

And unenhanced brain MRI is an alternative means of showing which tissue is already dead, while MRI perfusion shows, in a fashion similar to CT perfusion, which tissue can still be saved. 

The options can add up to a lot of images for a single stroke patient. Provider people who methodically manage the logistics of acquiring, organizing and transmitting massive image sets put their patients in position for good outcomes, Dym suggests. They also put their own organizations in position to earn high marks from accrediting bodies such as The Joint Commission. 

This begins with separating out initial head CTs for immediate interpretation but doesn’t end there, Dym says. For example, vRad has a software-based system in place to automatically route the subsequent advanced studies to the same radiologist that read the patient’s initial head CT. “This has been a big advance for us,” Dym says. “We’re making sure we maintain continuity of care while also achieving the dual aims of high accuracy and fast turnaround times.”

Having covered the basics, Dym says he hopes many radiologists, radiology administrators and “anyone who has a hand in making decisions around stroke care” will register for the June 28 webinar he’s co-hosting with vRad chief medical officer Dr. Benjamin Strong, Adapting Your Stroke Imaging Program for Success in the New DAWN Paradigm.

“It’s going to be exciting just to inform people who might not be aware of what’s happening here,” he says. “The 24-hour window is the most significant change in stroke care I’ve seen since I started 20 years ago. In fact, I believe it’s going to have a bigger impact on patient care than anything else I’ve ever been a part of.”