Research Alert: 3D MRI: Promise for Detecting Diseased Arteries

 

Radiologists can possibly utilize a new, 3D MRI technique as a screening tool to prevent stroke and heart attack, according to researchers at Sunnybrook Health Sciences Centre, Toronto.

 

The group is the first in the world to show how the noninvasive approach may detect a specific type of dangerous plaque in the arteries of high-risk patients. As a result, physicians may gain a closer, more in-depth look into diseased arteries and see information to which they did not have access previously. The researchers anticipate a potential change in "the standard of imaging everywhere."

 

"There's been a major sea change in our research," said Alan Moody, MD, lead investigator and radiologist in chief in the center's Department of Medical Imaging, who brought the 3D MRIPH technique to Canada from England. "We now know that the composition of carotid artery plaque is likely to be more predictive of future stroke events than the amount of narrowing in the blood vessel. Complicated plaque increases the risk of stroke or heart attack regardless of the degree of narrowing within the artery."

 

Through magnetic resonance imaging of plaque hemorrhage, radiologists can detect the bleeding that occurs within a plaque in an artery. Moody explained that the detection of bleeding within the walls of diseased carotid arteries may allow physicians to stabilize the plaque before it causes a vascular event, such as stroke, heart attack, or death.

 

Moody and his team applied the technique on the carotid arteries of 11 patients, ages 69 to 81. They surgically removed complicated plaques from the patients' diseased arteries and analyzed them under a microscope. Results of the study, which were published in the October 2008 edition of Radiology, demonstrated strong agreement between the lesions identified by the MRI as complicated plaques and the microscopic analysis of the tissue samples.

 

Conventional plaque-detection techniques include traditional ultrasounds, CT scans, and MRIs, which focused on the degree of narrowing of the blood vessel. On the other hand, the new MRI technique looks at the disease within the vessel wall, often before it causes significant narrowing. The researchers say the technique, therefore, serves as an early warning signal with the ability to flag a physician to a patient's risk and allow them to treat the problem before it escalates into a full-blown blockage.

 

"This technology gives us information we've never had before," Moody said. "It tells us how dangerous the plaque is and if it is likely to rupture. Until recently, we didn't know the specifics about the type of blockage; we only went by how much narrowing it caused to the blood flow. If the narrowing was severe, it could be taken out surgically. Now, it can tell us information about the plaque before it is causing major problems."

 

The researchers hope that the new technique can help select appropriate patients for plaque-removal surgery. The team is collaborating with scientists and clinicians across Canada through the Canadian Atherosclerosis Imaging Network to perform larger, more powerful trials.

 

—E. Sanchez