Coronary artery stent evaluation by combining iterative reconstruction and high-resolution kernel at coronary CT angiography.

PURPOSE To evaluate stent lumen visualization by combining high-resolution cardiac kernel and the iterative reconstruction (iDose) on an anthropomorphic moving heart phantom and in patients at coronary computed tomography (CT) angiography. MATERIALS AND METHODS We used the moving heart phantom and a 64 detector-row CT, retrospectively gated helical scanning, and image reconstruction. The heart rate was set at nonpulsating condition of 0 beats/min, 50 beats/min, and 80 beats/min. The 120-kV images were reconstructed in synchronization with electrocardiogram data using filtered back projection (FBP) or iDose algorithm and standard kernel/filter (CB) or high-resolution kernel/filter (CD). We measured image noise, the kurtosis, and stent lumen diameter in the phantom study. We also assessed the visual inspections by two radiologists. RESULTS With cardiac motion at 50 and 80 beats/min, the difference of kurtosis improved with CD relative to CB (P < .05). iDose algorithm with level 7 provided lowest noise, with no statistically significance in difference of the kurtosis relative to level 4 (P > .05). Without cardiac motion at 0 beats/min, the stent lumen diameter measurements with CD kernel were better relative to CB kernel (P < .05). In addition, no significant difference was found in stent lumen diameter between iDose level 4 and level 7 (P > .05). CONCLUSION The use of iDose and a sharp kernel allowed improved stent visualization at a lower radiation dose.