Reduced radiation dose with model based iterative reconstruction coronary artery calcium scoring

Area of Science:

• Radiology
• Cardiovascular Imaging
• Medical Physics

Background:

• Coronary artery calcium (CAC) scoring is crucial for personalized cardiac risk assessment.
• Optimizing CAC scanning protocols to reduce radiation dose while maintaining diagnostic accuracy is an ongoing challenge.

Purpose of the Study:

• To evaluate the efficacy of a model-based iterative reconstruction algorithm, forward projected model-based iterative reconstruction (FIRST), for reduced radiation dose CAC scanning.
• To assess the agreement between reduced dose FIRST and standard dose filtered back projection (FBP) CAC imaging using 320-detector row CT.

Main Methods:

• Prospective analysis of 100 patients undergoing both reduced and standard radiation dose CAC scans on a 320-detector row CT scanner.
• Comparison of CAC scores obtained with reduced dose FIRST reconstruction versus standard dose FBP reconstruction.
• Stratification of patients into Agatston categories for agreement analysis.

Main Results:

• Excellent agreement (81%, kappa 0.74) was observed between reduced dose FIRST and standard dose FBP CAC imaging.
• Median radiation exposure was reduced by 75% in the reduced dose scans (0.35 mSv) compared to standard dose scans (1.37 mSv).

Conclusions:

• Reduced radiation dose CAC scanning with FIRST reconstruction demonstrates excellent agreement with standard dose FBP imaging on 320-CT.
• This technique enables a significant 75% reduction in radiation exposure for CAC assessment, facilitating individualized cardiac risk stratification.