Inter-Observer Agreement and Image Quality of Model-Based Algorithm Applied to the Coronary Artery Disease Reporting and Data System Score

Abstract Purpose: To evaluate the inter-observer agreement of the CAD-RADS reporting system and compare image quality between model-based iterative reconstruction algorithm (MBIR) and standard iterative reconstruction algorithm (IR) of low dose cardiac computed tomography angiography (CCTA). Methods: One-hundred-sixty patients undergone a 256-slice MDCT scanner using low-dose CCTA combined with prospective ECG-gated techniques were prospectively enrolled. CCTA protocols were reconstructed with both MBIR and IR. Each study was evaluated by two readers using the CAD-RADS lexicon. Vessels enhancement, image noise, SNR, and CNR were computed in the axial native images and inter-observer agreement was assessed. Radiation dose exposure as dose–length product (DLP) and effective dose (ED) were finally reported. Results: The overall agreement was very good (k = 0.90). Moreover, a significantly higher value of subjective qualitative analysis, SNR, and CNR in MBIR images compared to IR were found, due to a lower noise level (p<0.05). The mean DLP measured was 63.9 mGy*cm and the mean effective dose was 0.9 mSv.Conclusion: Inter-observer agreement of CAD-RADS was excellent confirming the importance, the feasibility, and the reproducibility of the CAD-RADS scoring system for CCTA. Moreover, lower noise and higher image quality with MBIR compared to IR were found.