Radiation Dose Reduction for Coronary Artery Calcium Scoring Using a Virtual Noniodine Algorithm on Photon-Counting...

Area of Science:

• Medical Imaging
• Radiology
• Cardiovascular Imaging

Background:

• Virtual noniodine (VNI)-based coronary artery calcium scoring (CACS) is hypothesized to be feasible at reduced radiation doses.
• Assessing the impact of radiation dose reduction on VNI algorithm accuracy is crucial for optimizing CACS protocols.

Purpose of the Study:

• To evaluate the feasibility and accuracy of VNI-based CACS at reduced radiation doses using a photon-counting detector (PCD)-CT.
• To determine the impact of radiation dose reduction on image quality and CACS accuracy.

Main Methods:

• A phantom simulating three chest sizes was scanned on a clinical PCD-CT at varying radiation doses (100%, 75%, 50%, 25%).
• VNI images were reconstructed at different energy levels and iterative reconstruction settings (55 keV/QIR1, 60 keV/QIR4).
• Image quality (image noise, contrast-to-noise ratio) and CACS accuracy were evaluated and compared to true noncontrast (TNC)-based CACS.

Main Results:

• Virtual noniodine (VNI) image noise was significantly lower than true noncontrast (TNC) noise, with further reductions at higher keV/reconstruction settings.
• Contrast-to-noise ratio (CNR) was higher for TNC but improved with VNI at 60 keV/QIR4.
• Coronary artery calcium scoring (CACS) using VNI showed strong correlation and agreement with TNC across all radiation doses, with clinically nonrelevant errors.

Conclusions:

• Virtual noniodine (VNI)-based coronary artery calcium scoring (CACS) is feasible on photon-counting detector (PCD)-CT.
• Reduced radiation doses can be employed for VNI-based CACS without compromising image quality or diagnostic accuracy.
• This approach offers a promising strategy for dose reduction in cardiac CT imaging.