A new cardiac magnetic resonance imaging (MRI) technique can noninvasively demonstrate blockage of the coronary arteries with high diagnostic accuracy, according to a study featured in the July issue of Radiology.
Researchers at Massachusetts General Hospital (MGH) and Harvard Medical School in Boston and Beneficencia Portuguesa Hospital in Sao Paulo, Brazil compared their new imaging technique against the current diagnostic standard, coronary angiography, which is an invasive procedure. The MRI findings yielded an accuracy of 88 percent.
"We have shown that cardiac MRI can be used reliably as an alternative to other more invasive detection techniques, due to its high diagnostic accuracy, its comprehensive evaluation of cardiac function, perfusion and viability and the lack of radiation exposure," said Ricardo C. Cury, M.D., lead author and director of clinical cardiac MRI at MGH.
More than 13 million Americans have coronary artery disease (CAD); it is the number one killer in the Western hemisphere. Although coronary angiography is the current standard for detecting CAD, it is an invasive procedure that involves running a tube from a blood vessel below the heart up toward the heart itself, and then releasing contrast material into the arteries so they are visible on x-rays. There is a need for a preliminary, noninvasive way to assess the arteries to learn if such invasive investigation is required.
The authors applied a technique called stress first-pass perfusion MRI in combination with a delayed contrast-enhancement technique. This approach is different than the typical MRI sequences used to investigate the coronary arteries. With this combined technique, the researchers injected patients with a contrast material and then performed MRI at timed intervals to see if there was heart muscle ischemia attributable to coronary artery blockage and if there was damage (either tissue death or scarring) that indicated a prior heart attack.