Effect of Acquisition Techniques, Latest Kernels, and Advanced Monoenergetic Post-Processing on Stent Visualization with 3rd Generation Dual Source CT

Aims To evaluate the effect of tube voltage, current kernels, and monoenergetic post-processing on stent visualization.

Materials and Methods A 6 mm chrome-cobalt peripheral stent was placed in a dedicated phantom and scanned with the available tube voltage settings of a 3rd generation dual-source scanner in single-energy(SE) and dual-energy(DE) mode. Images were reconstructed using latest convolution kernels and monoenergetic reconstructions (40 – 190 keV) for DE. Sharpness of stent struts(S), stent struts width(SW), contrast-to-noise ratios(CNR), and pseudo-enhancement(PE) between the vessel with and without stent were analyzed using an in-house built automatic analysis tool. Measurements were standardized through calculated z-scores. Z-scores were combined for stent(SQ), luminal(LQ), overall depiction quality(OQ) by adding S&SW, CNR&SW&PE, and S&SW&CNR&PE. Two readers rated overall stent depiction on a five-point Likert scale. Agreement was calculated using linear weighted kappa. Correlations were calculated using Spearmanʼs rho.

Results Maximum values of S and CNR were 1690.8HU/pixel for [DE; 100/Sn150; Qr59,40 keV], and 50,0 for [SE;70 kV; Bv36]. Minimum values of SW and PE were 2.615 mm for [DE; 80 to 90/Sn150 kV; Qr59; 140 to 190 keV] and 0,12HU for [DE; 80/Sn150 kV; Qr36; 190 keV]. Best combined z-scores of SQ, LQ, and OQ were 4.53 for [DE; 100/Sn150 kV; QR59; 40 keV], 1.23 for [DE; 100/Sn150 kV; Qr59; 140 keV], and 2.95 for [DE; 90/Sn150 kV; Qr59; 50 keV]. Best OQ of SE was ranked third with 2.89 for [SE; 90 kV; Bv59]. Subjective reading showed excellent agreement with kappa = 0.86 and correlated well with OQ(rho = 0.94,p < 0.001).

Conclusions In conclusion, combining DECT acquisition with the latest kernels and monoenergetic post-processing allows for improved stent visualization as compared with SECT. The best overall results were obtained for monoenergetic reconstructions with 50 keV from DECT 90/Sn150 kV acquisitions using kernel Qr59.

Publication History

Article published online:
11 May 2021