TUESDAY, Sept. 16 (HealthDay News) -- Canadian researchers say that three-dimensional MRI may prove to be a useful screening tool for patients at high risk for stroke, a new report suggests.

In a study, published in the October issue of Radiology, researchers at Sunnybrook Health Sciences Centre in Toronto found 3-D MRI accurately detected bleeding within the walls of diseased carotid arteries.

When major arteries are affected by atherosclerosis, fatty deposits -- or plaques -- accumulate on the inner lining of the vessel walls. Over time, this causes narrowing and restricts blood flow or completely blocks the arteries.

New studies point to the composition of complicated plaques as a leading cause of vascular issues and death. Previous, they believed that this narrowing, called stenosis, was responsible for most heart attacks or strokes.

"There's been a major sea change in our research," Dr. Alan R. Moody, of the University of Toronto, said in a news release issued by the journal's publisher. "We now know that the composition of carotid artery plaque is likely to be more predictive of future stroke events than the amount of stenosis in the vessel."

In the study, the research team found matches between the lesions identified by the MRI as complicated plaques in 11 patients and the analysis under a microscope of the samples removed from these patients' diseased arteries.

"With high spatial resolution 3-D MRI, we are able to noninvasively analyze the tissue within the artery wall and identify small bleeds within rupture-prone plaques that may put patients at risk for future stroke," Moody said.

The MRI tool would be ideal to screen high-risk patients for complicated carotid plaques and to monitor the effects of other treatments to slow the disease's progression, Moody said, adding that the technique is quick and easy to perform and interpret, he said.

More information

The National Heart, Lung, and Blood Institute has more about atherosclerosis.