Effects of Iterative Reconstruction Technique on Image Quality in Cardiac CT Angiography: Initial Experience

Abstract

Objective: Iterative reconstruction algorithms offer potential radiation dose reduction while maintaining image quality.  We attempted to compare image quality parameters of iterative reconstruction and conventional filtered back-projection (FBP) quantitatively in cardiac CT angiography, using second generation dual-source CT technology.

Methods: Ten patients were scanned using retrospective ECG-gated dual-source CT for assessment of native coronary artery disease. Multiphase datasets were reconstructed using FBP and iterative reconstruction techniques. Image noise was measured throughout 20 phases of the cardiac cycle (at varying tube currents). Contrast-to-noise ratios (CNR) were compared at 9 specific coronary artery locations in diastole.

Results: In all evaluated coronary artery locations, the CNR was significantly improved with iterative reconstruction when compared to conventional FBP (improvement: 39.5 ± 2.8%, p<0.05). Iterative reconstruction demonstrated less image noise across all cardiac phases (reduction: 22.1 ± 4.0%, p<0.05).

Conclusions: Iterative reconstruction offers the potential to increase CNR in cardiac CTA. Our experience suggests that iterative reconstruction algorithms have the potential to reduce radiation doses while maintaining similar objective image quality measures such as CNR and noise levels versus standard FBP reconstructions. Further work with comparison to invasive coronary angiography is needed to ensure maintained diagnostic accuracy.