Coronary artery calcium scoring: expanding the new standard by photon-counting detector CT—Part I: Impact of tube voltage, tube current, slice thickness, and quantum iterative reconstructions - Scorecard - MDSpire
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Coronary artery calcium scoring: expanding the new standard by photon-counting detector CT—Part I: Impact of tube voltage, tube current, slice thickness, and quantum iterative reconstructions
Clinical Scorecard: Advancements in Coronary Artery Calcium Scoring Using Photon-Counting Detector CT: Part I - Effects of Tube Voltage, Tube Current, Slice Thickness, and Quantum Iterative Reconstructions
At a Glance
Category
Detail
Condition
Coronary artery calcium (CAC) scoring as a predictor of cardiovascular events
Key Mechanisms
Photon-counting detector CT (PCD-CT) improves spatial resolution, dose efficiency, HU stability, image noise, and contrast-to-noise ratio compared to energy-integrating detector CT (EID-CT)
Target Population
Borderline or intermediate risk patients for cardiovascular disease requiring CAC scoring
Care Setting
Radiology and cardiology imaging centers using CT technology
Key Highlights
Current CAC scoring standards (120 kVp, 3 mm slices) have high inter- and intrascanner variability leading to potential risk reclassification.
PCD-CT offers improved quantification accuracy of coronary calcifications compared to EID-CT with potential for dose reduction and better reproducibility.
A new radiation dose-reduced protocol using PCD-CT with varied tube voltage, slice thickness, and iterative reconstruction levels was proposed and compared to multivendor EID-CT protocols.
Guideline-Based Recommendations
Diagnosis
Use CAC scoring for reclassification of borderline or intermediate cardiovascular risk patients as per 2019 ACC/AHA guidelines.
Apply a standard CAC scoring threshold of 130 HU for lesion detection.
Management
Consider adopting reduced tube voltage (e.g., 90-100 kVp) and thin-slice reconstructions (1 mm) with higher iterative reconstruction levels to improve CAC score reproducibility and reduce radiation dose.
Utilize PCD-CT technology where available to enhance CAC quantification accuracy.
Monitoring & Follow-up
Perform multiple scans with slight repositioning to assess interscan variability and ensure reproducibility of CAC scores.
Monitor image noise levels to remain within target thresholds (20-23 HU lower limit, 30-35 HU upper limit depending on phantom size) to avoid false positives.
Risks
High image noise can cause false-positive CAC lesions.
Variability in scan positioning can lead to significant changes in CAC scores and potential risk reclassification.
Patient & Prescribing Data
Patients undergoing CT-based coronary artery calcium scoring, especially those at borderline or intermediate cardiovascular risk
Reduced radiation dose protocols using PCD-CT with optimized acquisition parameters can maintain or improve CAC scoring accuracy while minimizing radiation exposure.
Clinical Best Practices
Adopt PCD-CT protocols with lower tube voltage (e.g., 90 kVp) and thin slice thickness (1 mm) combined with quantum iterative reconstruction to enhance score reproducibility.
Use standardized phantom-based validation to compare CAC scoring protocols across different CT systems.
Ensure consistent patient positioning and consider multiple acquisitions to reduce variability in CAC quantification.
Maintain image noise within recommended thresholds to balance image quality and radiation dose.
by Nicola Fink, Lennart R. Koetzier, Emese Zsarnoczay, Milan Vecsey-Nagy, Dmitrij Kravchenko, Muhammad Taha Hagar, Jim O’Doherty, Moritz C. Halfmann, Pal Suranyi, Gijs D. van Praagh, Jens Ricke, Pal Maurovich-Horvat, Tobias Bäuerle, Martin J. Willemink, Akos Varga-Szemes, Tilman Emrich
