Impact of different tube voltages on the evaluation of coronary artery stents with ultra-high-resolution photon-counting detector CT:a phantom study

SUN Yue; XU Cheng; ZOU Limiao; WANG Ming; YU Xianbo; YU Yang; WANG Yining

doi:10.19300/j.2024.L21693

Abstract：Objective To investigate the impact of different tube voltages on the evaluation of coronary stents using ultra-high-resolution(UHR)photon-counting detector computed tomography(PCD-CT).Methods Six stents,approximately 3 mm in diameter and made from different materials,were placed inside artificial coronary vessel phantoms.UHR-PCD-CT scans of the stent were performed using different tube voltages(140 kV and 120 kV)and orientations(0°and 90°)relative to the z-axis of the scanning device.A total of 144 image datasets were acquired using various combinations of scanning and reconstruction parameters.Subjective scores and objective image quality were assessed.Objective metrics included the stent lumen attenuation increase ratio(SAIR),edge rise distance(ERD),and inner diameter of the stent.Inter-observer agreement for subjective image quality scoring was assessed using Cohen's Kappa test.Paired-sample t-tests or Wilcoxon tests were used to compare the image quality metrics of stents at different orientations(0° and 90°)under the two tube voltages.Multivariate generalized linear mixed-effects models were employed to investigate the impact of high tube voltage(140 kV)on the evaluation of coronary stents.Results For stents in the 0° orientation,no statistically significant differences were observed in subjective image quality scores,SAIR values,ERD values,and in-stent diameters between scans at 120 kV and 140 kV tube voltage(all P>0.05).For stents in the 90°orientation,imaging at 140 kV resulted in higher SAIR values,lower ERD values,and larger in-stent diameters compared to 120 kV(all P<0.05).For both 0°and 90°orientations,140 kV significantly increased SAIR values(both P<0.05).Additionally,for stents in the 90°orientation,140 kV increased the measured in-stent diameter and reduced ERD values(both P<0.05).Conclusions Compared to 120 kV,a tube voltage of 140 kV can reduce beam hardening artifacts associated with coronary stents in UHR-PCD-CT imaging.As the angle of the coronary stent relative to the z-axis increases,the higher tube voltage further improves stent sharpness and increases the measured in-stent diameter.However,the use of higher tube voltage also results in increased radiation dose,necessitating a comprehensive evaluation in clinical applications.