Researchers at Mount Sinai School of Medicine, New York, have developed a magnetic resonance imaging technique that for the first time allows radiologists to snap high-resolution pictures of plaques inside blood vessels that feed the heart.
Although still early in development, the technique would let doctors noninvasively diagnose the fatty buildups inside coronary arteries that could cause heart attacks. If further study corroborates the early experiments, MRI exams of coronary vessels could become commonplace in three to five years, researchers said. Patients with dangerous plaques then could be aggressively treated with cholesterol-lowering drugs and monitored with MRI. The regimen could reduce the need for angioplasty and bypass surgery.
The results of the MRI pilot study, involving eight healthy subjects and five with heart disease, were presented last week in Chicago at the 85th annual scientific meeting of the Radiological Society of North America.
"For the first time we have a way to see the plaques and differentiate between those that appear to be stable and those that are `angry' and prone to rupture," said Zahi Fayad, assistant radiology professor at Mount Sinai, who leads the research.
"We know that the plaque that's considered to be soft and of a certain shape, a crescent shape, is the one that will cause a heart attack," he explained.
"This is terrific," said Beatty Hunter, M.D., a cardiologist and executive medical director at the New England Heart Institute at Catholic Medical Center, Manchester, N.H. "If this is validated with bigger studies, it could be a significant breakthrough."
Today, cardiologists usually diagnose such plaques with angiography. The X-ray technique exposes patients to radiation and requires injection of an opaque dye that indicates the presence of plaques indirectly. These images lack information about the type of plaque involved.
Ultrafast computed tomography scanners also can freeze heart motion, and today some doctors use the scanners to screen patients at risk for heart disease. But the CT technique is controversial, in part because calcified plaques are usually stable and unlikely to lead to heart attacks. Doctors sometimes thread tiny ultrasound probes inside coronary vessels, but this invasive test is usually reserved for particularly difficult cases.
With MRI, Fayad said, doctors could easily monitor questionable plaques with serial exams, because the technique is noninvasive, quick and radiation-free. MRI studies are also cheaper, typically costing several hundred dollars compared with about $3,500 for an angiography exam.
Fayad's team used an MRI optimized for cardiac work from General Electric Medical Systems, Milwaukee, which also helped fund the research.