Each year, nearly 800,000 people in the United States suffer strokes, making cerebrovascular disease the nation’s third leading cause of death (behind heart disease and cancer). Virtually all of these patients end up in hospital emergency departments, where the ability to distinguish between ischemic strokes and the less common hemorrhagic strokes (which account for approximately 13% of cases) is crucial to determining the most effective course of treatment. Rapid triage and intervention are essential elements of a successful stroke program.
In 2007, the Stroke Center at Millard Fillmore Gates Circle Hospital (MFGCH), Buffalo, New York, transitioned from MRI to 64-detector CT for stroke triage, and in 2009, the center upgraded to a 320-detector scanner. The new protocol has enabled the program to take some patients from ambulance to scanner, saving critical time and freeing valuable emergency-department beds.
“At this point, we triage almost 100% of our stroke patients on our 320-slice scanner. We can acquire whole-brain perfusion images, which you cannot do on other systems. It’s really the way to go, in terms of both the time it takes and the results.”
—Erik Saluste, imaging manager
Millard Fillmore Gates Circle Hospital, Buffalo, New York
MFGCH implemented the 320-slice Aquilion ONE multidetector CT scanner from Toshiba America Medical Systems, Tustin, California, in June 2009, after using a 64-slice CT unit from the same vendor for stroke triage since 2007.
“Without a dedicated MRI unit, it’s hard to get patients on there in an acute setting,” Michael Miller, MD, radiologist at MFGCH, explains. “There were issues, too, with screening patients who arrive confused and unable to give a history, which posed potential risks with putting them in an MRI environment. Regarding gadolinium toxicity and nephrogenic systemic fibrosis, that created problems getting rapid assessments of renal function, so for many reasons, we decided to emphasize the CT arm of the workup.”
The state of New York requires that stroke patients receive a head scan without contrast within 20 minutes of reaching the emergency department and an initial interpretation of that scan within 40 minutes; Erik Saluste, imaging manager, says that MFGCH is now far exceeding that requirement, obtaining a head scan without contrast, a perfusion image with contrast, and a CT angiogram (CTA) of the head and neck within 45 minutes.
“CTA doesn’t overestimate stenosis as much as MRI does,” Saluste notes. “You’re much better off with CT/CTA, and though we might still use MRI for additional imaging, it’s really up to the physician. There are some who still prefer MRI over CT, but that’s a very small population.”
From Emergency Department to Hospital Bed
According to Saluste, the Stroke Center at MFGCH sees 10 to 15 stroke patients a day, sometimes intercepting these patients directly from the ambulance before they even reach the emergency department. “I think the fact that we expedite things so well relieves the emergency department of patients who might otherwise be sitting there for hours,” Saluste says. “The stroke patients aren’t likely to spend a lot of time in the emergency department after they’ve been imaged. Many times, the patient is brought directly to intervention after CT. We’re providing much more timely care than we ever have—we get a quick scan and a very comprehensive study on their vessels and their brain tissue.”
The Stroke Center has neurologists and neuroradiologists on-site 24/7; Miller says that the stroke team is currently responding to noncontrast head CT within 20 to 30 minutes of the patient’s arrival. “Nearly all acute neurologic presentations are triaged to our CT stroke protocol,” he says. “Then, we determine whether the next step is further imaging or appropriate medical therapy, which can consist of thrombolytics and/or heparin therapy, if appropriate.”
Miller recalls attempting to handle the same patient load using MRI for triage; the results, he says, were far less efficient than those obtained using 320-slice CT. “Believe it or not, sometimes we have two or three workups going on at the same time,” he says. “Pushing those patients through one MRI suite wasn’t working well for us. The room time for MRI was 20 to 30 minutes; for the CT stroke protocol, it’s around 10.”
He adds that CT—even top-of-the-line (and thus expensive) CT—is more cost effective than MRI because of the increased throughput that