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U.Va. RESEARCHERS IMAGE ANEURYSMS IN THE AORTA WITH MRI TECHNIQUE

Ruptured aneurysms in the largest blood vessel in the body, the aorta, kill about 15,000 people in the U.S. annually, according to the Society of Interventional Radiology. Many of these deaths happen when aortic aneurysms suddenly break open in the abdomen, usually just above where the aorta divides to supply blood to the pelvis and legs. This can be a medical emergency causing profuse bleeding. Less than half of all people with a ruptured aorta in the abdomen survive, according to the National Institutes of Health.

Reporting in the March 2 edition of the journal “Circulation,” researchers at the University of Virginia Health System have demonstrated for the first time that magnetic resonance imaging (MRI) can distinguish, non-invasively, the components of atherosclerotic plaque in abdominal aneurysms.

Using a common contrast agent called gadolinium-DTPA, U.Va. cardiologist Dr. Christopher Kramer and his colleagues successfully imaged the thin, fibrous cap on aortic plaque, one key characteristic of plaque in smaller blood vessels such as the coronary and carotid arteries that are more prone to rupture and cause heart attack and stroke.

“The ability to image the characteristics of plaque is something new,” Kramer said, “and we were pleased that we were able to image within the plaque and distinguish the fibrous cap.  Eventually over the next few years, we hope to image these plaque components in the smaller carotid and coronary arteries, though they may have different characteristics than plaque in the aorta,” Kramer said.

In the study, Kramer and his colleagues recruited 23 patients for an MRI of their aortic aneurysm before scheduled surgery to repair the aneurysm. A U.Va. surgeon, Dr. John Kern, then resected a small slice of the aortic aneurysm that had been imaged by MRI. The slice of aorta was examined by U.Va. pathologists, who confirmed that the patients had between one and three layers of plaque containing either a fibrous cap, lipid core or thrombus. The MRI findings matched the pathological findings in 21 of 23 patients.

This study on how MRI can identify the fibrous cap in abdominal aortic aneurysms can be found online at http://circ.ahajournals.org/content/vol109/issue8/index.shtml.

March 31, 2004