A Phantom Experimental Study on Improving the Imaging Quality of Stent CT at a Fast Heart Rate

Objective: This study aimed to investigate the impact of different imaging parameters on stent imaging and stenosis assessment in a fast heart rate model. The goal was to reduce the radiation dose while ensuring image quality, and to provide a theoretical basis for optimizing computed tomography (CT) imaging parameters for stent imaging in patients with fast heart rates in future clinical practice. Methods: Different imaging parameters were set to obtain multiple sets of CT images of stents in a fast heart rate model. Four coronary artery stents with different internal diameters were used. Each stent was set to four levels of stenosis. Two different concentrations of iodine contrast agents were injected in batches. The Canon 320 CT scanner was used to perform scans at 100 kV and 120 kV tube voltages, and image reconstruction was performed using the stent reconstruction mode. Two radiologists, with more than three years of experience in coronary CT diagnosis, used a 5-point scoring method to subjectively evaluate image quality based on stent visualization, image quality, and stenosis assessment. Multiple regression analysis was conducted to assess the influence of stent diameter, stenosis level, tube voltage, and iodine contrast agent concentration on the subjective image quality scores. Results: The structures of the four stents could be visualized in all parameter combinations, but there were significant differences in the intraluminal display. The stent diameter, stenosis level, and iodine contrast agent concentration had a significant impact on the subjective image quality scores. The scores increased as the stent diameter increased and the stenosis level and iodine contrast agent concentration decreased. Moreover, the stent diameter had the strongest impact on the scores. Tube voltage did not significantly affect the subjective image quality scores. Conclusion: In fast heart rate conditions, the stent diameter, stenosis level, and iodine contrast agent concentration directly affect the image quality of stent CT imaging. Conversely, tube voltage had no impact on image quality. Our findings provided a theoretical basis for optimizing stent imaging protocols in patients with fast heart rates.