MRI predicts women's coronary event risk: new global perfusion index.
NEW ORLEANS -- Cardiac magnetic resonance perfusion imaging appears to be the study of choice for assessing cardiac event risk in women with symptoms of ischemic heart disease, Dr. Mark Doyle said at the annual meeting of the American College of Cardiology.
A global myocardial perfusion index obtained using cardiac magnetic resonance imaging with gadolinium perfusion significantly outperformed radionuclide gated SPECT imaging and quantitative coronary angiography in a sub-study of the Women's Ischemia Syndrome Evaluation (WISE), according to Dr. Doyle of Allegheny General Hospital, Pittsburgh.
WISE is a National Heart, Lung, and Blood Institute sponsored prospective multicenter study focusing on development of improved methods of detecting coronary artery disease in women. Dr. Doyle reported on 133 WISE participants with ischemic symptoms at Allegheny General Hospital who underwent baseline cardiac magnetic resonance perfusion imaging, radionuclide gated SPECT, and quantitative coronary angiography, and were then followed for 38 months.
The cardiac magnetic resonance (CMR) perfusion index provides a global measure of coronary artery disease. In contrast, the strengths of radionuclide imaging and angiography lie in their ability to identify regional coronary disease. Since women are more likely than men to have diffuse coronary disease rather than the classic markedly stenotic lesions, the hypothesis was that the CMR perfusion index would enable physicians to identify women with physiologically significant CAD even in the absence of focal coronary disease, he explained.
This proved to be the case. Of the 133 women, 100 were classified as low risk by CMR perfusion imaging. Their cumulative rate of nonfatal MI or death during more than 3 years of follow-up was 3%. The event rate proved to be sevenfold greater in the 33 women identified as high risk.
Neither radionuclide imaging nor quantitative angiography could match that performance. For example, SPECT imaging classified 107 women as low risk; their event rate was 6%--twice that of women rated low risk by CMR--while the high-risk group by SPECT had a 14% event rate.
The greatest prognostic power was obtained using CMR perfusion imaging in concert with angiography. This combined approach identified a low-risk group of 73 women with a cumulative event rate of 30, an intermediate-risk group of 47 women with an 11% event rate, and a high-risk group having a 37% event rate during follow-up.
"Cardiac magnetic resonance imaging is already the gold standard in the areas of anatomy, function, and viability. Now, as well, we've shown additive value for perfusion imaging," the cardiologist observed.
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|Title Annotation:||Women's Health; Magnetic Resonance Imaging|
|Publication:||Family Practice News|
|Date:||Jul 15, 2004|
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