Quantification accuracy in photon-counting detector CT for coronary artery calcium score: a pilot study

Area of Science:

• Medical Imaging
• Radiology
• Cardiovascular Imaging

Background:

• Coronary artery calcium score (CACS) is crucial for cardiovascular risk assessment.
• Photon-counting detector CT (PCD-CT) offers potential advancements in CT imaging.
• Optimizing PCD-CT scanning parameters is essential for accurate CACS measurement and dose reduction.

Purpose of the Study:

• To validate the accuracy of CACS measurements using PCD-CT across various scanning settings.
• To identify optimal PCD-CT scanning parameters balancing accuracy and radiation dose.
• To compare PCD-CT CACS measurements with a reference standard.

Main Methods:

• A CACS phantom and 12 patients were scanned using PCD-CT with varied modes (sequence, flash) and tube voltages (90kV, 120kV, 140kV, Sn100kV, Sn140kV).
• PCD-CT acquisitions were reconstructed at 70keV.
• Energy-integrating detector CT (EID-CT) in sequence mode served as the reference standard for CACS calculation (Agatston, mass, volume scores).

Main Results:

• PCD-CT demonstrated excellent agreement with the reference standard for CACS (ICC > 0.99 for phantom, ICC > 0.98 for patients).
• Radiation dose was reduced by 16-75% with PCD-CT in flash mode compared to the reference.
• No significant reclassification of CACS categories occurred in patient scans.

Conclusions:

• PCD-CT provides repeatable and accurate CACS measurements across diverse scanning protocols.
• PCD-CT enables significant radiation dose reduction while maintaining diagnostic accuracy.
• Recommended clinical settings for PCD-CT CACS include Sn100kV, 90kV, and 120kV in flash mode at IQ20.