Coronary artery calcium quantification from contrast enhanced CT using gemstone spectral imaging and material...

Area of Science:

• Cardiovascular Imaging
• Radiology
• Medical Physics

Background:

• Coronary artery calcium (CAC) scoring is crucial for cardiovascular risk assessment.
• Standard CAC measurement requires a dedicated unenhanced CT scan, increasing radiation dose and scan time.
• Dual-energy CT offers potential for image post-processing to derive virtual unenhanced images.

Purpose of the Study:

• To evaluate the feasibility of measuring CAC from low-dose contrast-enhanced coronary CT angiography (CCTA).
• To determine if virtual unenhanced images generated from dual-energy CCTA can replace standard unenhanced CT for CAC quantification.
• To assess the radiation dose implications of this combined imaging approach.

Main Methods:

• 52 patients underwent both standard unenhanced cardiac CT and prospectively ECG-triggered, dual-source, dual-energy CCTA (gemstone spectral imaging - GSI).
• Virtual unenhanced images were reconstructed from GSI CCTA at 70 keV with selective iodine material suppression.
• CAC scores (Agatston, Volume, Mass) from virtual unenhanced CT were compared to those from standard unenhanced CT using linear regression analysis.

Main Results:

• Successful iodine subtraction was confirmed by a significant decrease in aortic attenuation on virtual unenhanced images (54 ± 8 HU vs. 64 ± 55 HU).
• Excellent correlation was observed between CAC scores derived from virtual unenhanced CT and standard unenhanced CT (r = 0.96 for Agatston and Volume, r = 0.92 for Mass).
• The combined CCTA acquisition with virtual unenhanced image generation results in a comparable or potentially lower radiation dose compared to separate scans.

Conclusions:

• Dual-source, dual-energy CCTA with gemstone spectral imaging (GSI) enables accurate CAC quantification.
• Virtual unenhanced imaging from GSI CCTA can effectively replace standard unenhanced CT for CAC scoring.
• This approach streamlines the cardiac CT examination, potentially reducing patient radiation dose and improving workflow efficiency.