Aortic valve and coronary artery calcium scoring: impact of half- versus standard-dose protocols

CT acquisition parameters and reconstruction techniques may affect the accuracy of calcium scoring measurements with a potential impact on clinical decision making. We evaluated the agreement of half- versus standard-dose protocols for assessment of aortic valve (AVCS HD and AVCS SD protocols) and coronary artery calcium scoring (CACS HD and CACS SD protocols) with and without the application of iterative reconstruction.

We enrolled 144 consecutive patients (mean age 83 ± 9 years) with known aortic stenosis undergoing 128-row prospective sequential CT with standard (120 kVp/20 mAs) and half-dose (120 kVp/10 mAs) protocols for both AVCS and CACS evaluation. The half-dose dataset was processed with and without iterative reconstruction. Agreement and precision of different protocols were evaluated using linear regression and Bland-Altman analysis. Additionally, we assessed the reclassification of cardiovascular risk based on the Mayo Clinic system and the likelihood of severe aortic stenosis using sex-specific categories.

Compared with the standard dose, the half-dose protocol with or without iterative reconstruction demonstrated optimum agreement for the evaluation of AVCS (r = 0.99; R² = 0.97) and CACS (r = 0.96; R² = 0.93). The half-dose iterative reconstruction protocol yielded a very low rate of reclassification aortic stenosis severity (1.4%) and cardiovascular risk (6.2%). The half-dose protocol resulted in 47.5% radiation dose reduction compared to standard dose (dose-length product: 8.5 ± 1.1 vs. 17.9 ± 2.7; p < 0.001).

Our findings suggest that the half-dose protocol with iterative reconstruction provides reliable and accurate results for both AVCS and CACS assessment. This evidence underscores the potential to optimize radiation dose while preserving the precision of diagnostic outcomes, thereby minimally impacting clinical management.