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Stress CMR vs. SPECT for Detection of CAD
Quick Takes
- In this study of 294 subjects who underwent vasodilator stress perfusion CMR and SPECT myocardial perfusion imaging, CMR performed more favorably for the detection of significant epicardial CAD, with AUC 0.88 vs. 0.74 (p < 0.001) and specificity 89% vs. 79% (p = 0.002).
- Regarding sensitivity, CMR was nonsuperior and noninferior to SPECT (74% vs. 64%, p = 0.127).
Study Questions:
What is the performance of vasodilator stress perfusion cardiac magnetic resonance (CMR) for detection of coronary artery disease (CAD), in comparison with that of single-photon emission computed tomography (SPECT) myocardial perfusion imaging?
Methods:
GadaCAD2 was an international, phase 3 trial with the primary aim of assessing gadobutrol-enhanced vasodilator stress perfusion CMR for the detection of CAD. As described in this manuscript, GadaCAD2 secondarily sought to assess the sensitivity and specificity of vasodilator perfusion CMR as compared with SPECT myocardial perfusion imaging (exercise or vasodilator stress with Tc-99m sestamibi or tetrofosmin). All subjects underwent anatomic coronary imaging with quantitative coronary angiography (significant epicardial CAD defined as ≥70% stenosis) or coronary CT angiography (significant CAD excluded if no coronary calcifications were present and luminal narrowing was <25% visually). Stress CMR and SPECT were performed within 4 weeks of each other. Key exclusion criteria were contraindications to CMR, prior coronary artery bypass grafting, and estimated glomerular filtration rate <30 ml/min/1.73 m2. Regadenoson and adenosine were acceptable vasodilators, and dipyridamole was also allowed for SPECT.
Results:
A total of 294 subjects were included in the analysis. The prevalence of significant CAD was 24.5%. CMR’s overall diagnostic performance was more favorable than that of SPECT (area under the receiver operating characteristic curve [AUC] 0.88 vs. 0.74, p < 0.001; accuracy 85% vs. 75%, p = 0.003; specificity 89% vs. 79%, p = 0.002). Regarding sensitivity, CMR was nonsuperior and noninferior to SPECT (74% vs. 64%, p = 0.127). SPECT had more false-positive and false-negative results than CMR.
Conclusions:
As compared with SPECT myocardial perfusion imaging, vasodilator stress CMR has superior specificity and accuracy for detection of obstructive CAD. Sensitivity of the two modalities is not significantly different.
Perspective:
Vasodilator CMR is an excellent “one-stop shop” modality for working up patients with cardiac symptoms and undifferentiated cardiomyopathies. Uptake of vasodilator CMR has been more robust in Europe than in the United States because of differences in factors such as magnet availability, payer preferences, and specialty training. This study did not evaluate positron emission tomography perfusion imaging, which has superior diagnostic performance compared with SPECT but very limited availability in the United States. One advantage of nuclear imaging over CMR is the potential to detect subclinical CAD by coronary calcium scoring, if an accompanying CT is performed for attenuation correction.
Clinical Topics: Noninvasive Imaging, Atherosclerotic Disease (CAD/PAD), Computed Tomography, Magnetic Resonance Imaging, Nuclear Imaging
Keywords: Coronary Artery Disease, Magnetic Resonance Imaging, Tomography, Emission-Computed, Single-Photon
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