Impact of monochromatic coronary computed tomography angiography from single-source dual-energy CT on coronary stenosis quantification

Background: In coronary CT angiography (CTA), stenosis evaluation is limited by artifacts such as blooming. Monochromatic reconstructions from single-source dual-energy coronary CTA have shown to reduce image noise and improve image quality.

Objective: The aim of this study was to analyze the impact of monochromatic coronary CTA reconstructions on stenosis quantification using invasive coronary angiography (ICA) as standard of reference.

Methods: Patients who were referred for clinically indicated assessment of coronary artery disease underwent coronary CTA and ICA within 4 months. In standard polychromatic coronary CTA images as well as 8 monochromatic series (50 keV-140 keV) luminal narrowing of coronary lesions was measured and compared to ICA with quantitative coronary angiography (QCA).

Results: In 37 patients with a mean age of 63.4 ± 8.2 years and a broad range of BMI (19.9-45.5 kg/m(2)), 124 lesions were studied. Throughout all the reconstructions, CT measurements showed a significant correlation with QCA (P < 0.001), except for reconstructions with 50 keV. Luminal narrowing of calcified and partly calcified lesions was generally overestimated, and underestimated in noncalcified plaques. After stepwise regression, reconstructions with 90 keV showed the best relation to QCA (P < 0.001, R2 = 0.9). Analysis by plaque composition suggested a superior performance of reconstructions at 90 keV for calcified and partly calcified plaques and at 140 keV for noncalcified plaques.

Conclusion: The use of monochromatic reconstructions improves the overall accuracy of lesion assessment. Combining reconstructions at 90 keV for calcified and partly calcified lesions and at 140 keV for noncalcified lesions yielded optimal results. Thus monochromatic reconstruction bears the potential to improve accuracy of coronary CTA.