New study favors CT perfusion over MRI for diagnosing acute ischemic stroke. Image Source: Thomas Jefferson University

A team of stroke experts from the West Virginia University Health Sciences Center have found that CT perfusion imaging may dramatically improve stroke diagnosis, according to a study published in the October issue of the Journal of Emergency Medicine.

The study showed that CT perfusion had 100 percent accuracy for detecting the acute ischemic stroke (AIS). If adopted, the researchers said that this advancement in stroke detection will mean dramatically faster diagnosis time—less than half the time of MRI screening—and enable physicians to provide more accurate and targeted care, thereby avoiding potentially life-threatening complications that can occur when thrombolytic drug therapy is used inappropriately.

Ansaar T. Rai, MD, and colleagues from the West Virginia University Health Sciences Center in Morgantown, W.Va., said that the objective of the study was to determine the utility of CT perfusion scans in diagnosing AIS. They correlated CT perfusion abnormalities in two contiguous supratentorial levels with diffusion weighted image (DWI) abnormalities on MRI—the gold-standard for stroke diagnosis—performed within one week in 422 suspected AIS patients.

Of the 157 AIS confirmed by DWI, 78 showed CT perfusion abnormalities (sensitivity 49.7 percent). All of the exams were performed with a mean of 35 minutes from the initial emergency department neurological exam, the authors wrote.

Rai and colleagues found that excluding small non-vascular territory strokes left 77 AIS with a total volume of infarcted tissue of more than 5 cc by DWI. Of these, 71 showed CT perfusion abnormalities (sensitivity 92.2 percent). Of the 265 patients without AIS, none showed CT perfusion abnormalities (specificity 100 percent).

“Our study reveals that the widespread use of CT perfusion is a practical way to help busy emergency departments save precious time in stroke diagnosis, to target treatment and reduce the risks of inappropriate thrombolytic use,” said Rai, assistant professor of neuroradiology and neurointerventional radiology. "CT perfusion was able to pinpoint strokes with high levels of accuracy, particularly the major intracranial vessel strokes that result in more devastating outcomes.”

The authors concluded that their results could change national stroke triage protocols.

According to the American Stroke Association (ASA), stroke is the third leading cause of death in the United States. Each year, 780,000 Americans will fall victim to stroke and more than 150,000 will die from the condition. The cost associated with stroke care is currently estimated to be $65 million.