CMR may be better than SPECT at diagnosing CAD in women

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 - Women

When diagnosing coronary artery disease (CAD) in women, cardiovascular magnetic resonance (CMR) may be a better option than SPECT, according to a study published in the March 11 issue of Circulation. The study found CMR to be more sensitive than SPECT in both sexes and there are no significant differences between the sexes with CMR, unlike SPECT.

John P. Greenwood, PhD, of the University of Leeds in the United Kingdom, and colleagues used data from the Clinical Evaluation of Magnetic Resonance Imaging in Coronary Heart Disease (CE-MARC) to compare the diagnostic accuracy of CMR and SPECT specific to sex. The original CE-MARC trial evaluated multiparametric CMS and SPECT in 752 patients with suspected CAD between 2006 and 2009.

Greenwood and colleagues used data from 235 women and 393 men with suspected angina who underwent CMR, SPECT and x-ray angiography as part of CE-MARC. CMR consisted of adenosine stress/rest perfusion, cine imaging, late gadolinium enhancement and magnetic resonance coronary angiography. SPECT was performed using a gated adenosine stress/rest protocol with 99m Tc-tetrofosmin. They compared perfusion-only components of CMR and SPECT and evaluated what factors could reduce their accuracy in women, including small heart size, disease pattern and breast size.

Significantly fewer women than men had CAD (23 percent overall vs. 50 percent). They found that the sensitivity of CMR to detect CAD was similar among men and women (88.7 percent vs. 85.6 percent) and specificity was similar as well (83.5 percent vs. 82.8 percent). CMR was more sensitive in both men and women when compared with SPECT, but specificity was similar.

The sensitivity of SPECT, however, was worse in women than in men (50.9 percent vs. 70.8 percent), but specificity was similar between the sexes (84.1 percent vs. 81.3 percent). Analysis of perfusion-only components found CMR outperformed SPECT in both men (area under the curve [AUC], 0.89 vs. 0.74) and women (AUC, 0.9 vs. 0.67).

The investigators found CMR was more sensitive than SPECT to detect single-vessel disease and multivessel disease in both sexes. Additionally, the lower accuracy of SPECT was more likely related to smaller heart size rather than breast attenuation.

“These findings, plus an absence of ionizing radiation exposure, mean that CMR should be more widely adopted in women with suspected coronary artery disease,” the authors wrote.