Initial exploration of coronary stent image subtraction using dual-layer spectral CT

  • Le Qin
  • ShengJia Gu
  • ChiHua Chen
  • Huan Zhang
  • ZhenBin Zhu
  • XingBiao Chen
  • Qun Han
  • FuHua Yan
  • WenJie YangEmail author
Computed Tomography



This study aimed to investigate the feasibility of coronary stent image subtraction using spectral tools derived from dual-layer spectral computed tomography (CT).


Forty-three patients (65 stents) who underwent coronary CT angiography using dual-layer spectral CT were included. Conventional, 50-keV (kilo electron-volt), 100-keV, and virtual non-contrast (VNC) images were reconstructed from the same cardiac phase. Stents were subtracted on VNC images from conventional (convsub), 100-keV (100-keVsub), and 50-keV (50-keVsub) images. The in-stent lumen diameters were measured on subtraction, conventional, and 100-keV images. Subjective evaluation of reader confidence and subtractive quality was evaluated. Friedman tests were performed to compare in-stent lumen diameters and subjective evaluation among different images. Correlation between stent diameter and subjective evaluation was expressed as Spearman’s rank correlation coefficient (rs). The diagnostic accuracy was assessed according to invasive coronary angiography (ICA) performed in 11 patients (20 stents).


In-stent lumen diameters were significantly larger on subtraction images than those on conventional and 100-keV images (p < 0.05). Higher reader confidence was found on 100-keV, convsub, 100-keVsub, and 50-keVsub images compared with conventional images (p < 0.05). Subtractive quality of 100-keVsub images was better than that of convsub images (p = 0.037). A moderate-to-strong correlation between stent diameter and subjective evaluation was found (rs = 0.527~0.790, p < 0.05). Higher specificity, positive predictive value, and negative predictive value of subtraction images were shown by ICA results.


Subtraction images derived from dual-layer spectral CT enhanced in-stent lumen visibility and could potentially improve diagnostic performance for evaluating coronary stents.

Key Points

• Dual-layer spectral CT enabled good subtractive quality of coronary stents without misregistration artifacts.

• Subtraction images could improve in-stent lumen visibility.

• Reader confidence and diagnostic performance were enhanced with subtraction images.


Computed tomography angiography Stents Subtraction technique 



Body mass index


Coronary computed tomography angiography


Volume of CT dose index


Dose length product




Effective dose


Heart rate


Hounsfield unit


Invasive coronary angiography


Intraclass correlation coefficient


In-stent restenosis


Kilo electron-volt


Negative predictive value


Percutaneous coronary intervention


Positive predictive value


Region of interest


Standard error of measurement


Virtual non-contrast


Window level


Window width



The authors thank Baisong Wang, PhD, a statistic teacher at Shanghai JiaoTong University, for providing statistical analysis. We also thank Yan Jiang and JianQing Sun for their great technical support.


The authors state that this work has not received any funding.

Compliance with ethical standards


The scientific guarantor of this publication is WenJie Yang.

Conflict of interest

The authors of this manuscript declare no relationships with any companies whose products or services may be related to the subject matter of the article.

Statistics and biometry

No complex statistical methods were necessary for this paper.

Informed consent

Written informed consent was waived by the Institutional Review Board.

Ethical approval

Institutional Review Board approval was obtained.


• retrospective

• cross-sectional study

• performed at one institution


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Copyright information

© European Society of Radiology 2019

Authors and Affiliations

  • Le Qin
    • 1
  • ShengJia Gu
    • 1
  • ChiHua Chen
    • 1
  • Huan Zhang
    • 1
  • ZhenBin Zhu
    • 2
  • XingBiao Chen
    • 3
  • Qun Han
    • 3
  • FuHua Yan
    • 1
  • WenJie Yang
    • 1
    Email author
  1. 1.Department of RadiologyRuijin Hospital Affiliated to Shanghai Jiaotong University School of MedicineShanghaiChina
  2. 2.Department of CardiologyRuijin Hospital Affiliated to Shanghai Jiaotong University School of MedicineShanghaiChina
  3. 3.Philips HealthcareShanghaiChina

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