First experience with single-source, dual-energy CCTA for monochromatic stent imaging

Area of Science:

• Cardiovascular Imaging
• Medical Physics

Background:

• Dual-energy CT (DECT) enables monochromatic image reconstruction, offering noise reduction in coronary computed tomography angiography (CCTA).
• Coronary stent imaging is susceptible to artifacts from strut material, potentially causing artificial luminal narrowing.

Purpose of the Study:

• To evaluate the impact of monochromatic CCTA image reconstruction on coronary stent imaging.
• To assess the accuracy of luminal diameter measurements in stented coronary arteries using different monochromatic energy levels.

Main Methods:

• Twenty-one patients with 62 coronary stents underwent dual-energy CCTA and quantitative invasive coronary angiography (QCA).
• Monochromatic CCTA images were reconstructed at various keV levels (50-140 keV).
• In-stent luminal diameter and attenuation were measured and compared with QCA.

Main Results:

• Monochromatic CCTA showed higher luminal attenuation within stents compared to the aortic root across all energy levels.
• Increasing monochromatic energy reduced luminal attenuation values.
• Stent diameter underestimation by monochromatic CCTA decreased from 90% at 50 keV to 37% at 140 keV, compared to 39% with standard CCTA.

Conclusions:

• Monochromatic CCTA is reliable for imaging coronary stents.
• Reconstructions below 80 keV are not recommended due to pronounced blooming artifacts and significant stent diameter underestimation.
• Higher monochromatic energy levels improve the accuracy of in-stent luminal diameter assessment.