Single- and dual-energy CT pulmonary angiography using second- and third-generation dual-source CT systems: comparison of radiation dose and image quality

  • Lukas LengaEmail author
  • Franziska Trapp
  • Moritz H. Albrecht
  • Julian L. Wichmann
  • Addison A. Johnson
  • Ibrahim Yel
  • Tommaso D’Angelo
  • Christian Booz
  • Thomas J. Vogl
  • Simon S. Martin
Computed Tomography



To evaluate radiation exposure and image quality in matched patient cohorts for CT pulmonary angiography (CTPA) acquired in single- and dual-energy mode using second- and third-generation dual-source CT (DSCT) systems.


We retrospectively included 200 patients (mean age, 65.5 years ± 15.7 years) with suspected pulmonary embolism—equally divided into four study groups (n = 50) and matched by gender and body mass index. CTPA was performed with vendor-predefined second-generation (group A, 100-kV single-energy computed tomography (SECT); group B, 80/Sn140-kV dual-energy computed tomography (DECT)) or third-generation DSCT (group C, 100-kV SECT; group D, 90/Sn150-kV DECT) devices. Radiation metrics were assessed using a normalized scan range of 27.5 cm. For objective image quality evaluation, dose-independent figure-of-merit (FOM) contrast-to-noise ratios (CNRs) were calculated. Subjective image analysis included ratings for overall image quality, reader confidence, and image artifacts using five-point Likert scales.


Calculations of the effective dose (ED) of radiation for a normalized scan range of 27.5 cm showed nonsignificant differences between SECT and DECT acquisitions for each scanner generation (p ≥ 0.253). The mean effective radiation dose was lower for third-generation groups C (1.5 mSv ± 0.8 mSv) and D (1.4 mSv ± 0.7 mSv) compared to second-generation groups A (2.5 mSv ± 0.9 mSv) and B (2.3 mSv ± 0.6 mSv) (both p ≤ 0.013). FOM-CNR measurements were highest for group D. Qualitative image parameters of overall image quality, reader confidence, and image artifacts showed nonsignificant differences among the four groups (p ≥ 0.162).


Third-generation DSCT systems show lower radiation dose parameters for CTPA compared to second-generation DSCT. DECT can be performed with both scanner generations without radiation dose penalty or detrimental effects on image quality compared to SECT.

Key Points

• Radiation exposure showed nonsignificant differences between SECT and DECT for both DSCT scanner devices.

• Dual-energy CTPA provides equivalent image quality compared to standard image acquisition.

• Subjective image quality assessment was similar among the four study groups.


Computed tomography angiography Pulmonary embolism Radiation dosage Diagnostic imaging Thorax 



Advanced modeled iterative reconstruction


Automated attenuation-based tube voltage selection


Body mass index


Contrast-to-noise ratio


Computed tomography


Volume CT dose index


Dual-energy computed tomography


Dose-length product


Dual-source computed tomography


Effective dose




Hounsfield units


Region of interest


Sinogram-affirmed iterative reconstruction


Standard deviation


Single-energy computed tomography



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

Compliance with ethical standards


The scientific guarantor of this publication is Lukas Lenga.

Conflict of interest

The authors of this manuscript declare relationships with the following companies: Julian L. Wichmann received speakers’ fees from GE Healthcare and Siemens Healthcare. Moritz H. Albrecht received speakers’ fees from Siemens Healthcare. However, all other authors report no potential conflict of interest. Data was controlled by authors with no potential conflict of interest.

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

  • Lukas Lenga
    • 1
    Email author
  • Franziska Trapp
    • 2
  • Moritz H. Albrecht
    • 1
  • Julian L. Wichmann
    • 1
  • Addison A. Johnson
    • 3
  • Ibrahim Yel
    • 1
  • Tommaso D’Angelo
    • 1
    • 4
  • Christian Booz
    • 1
  • Thomas J. Vogl
    • 2
  • Simon S. Martin
    • 1
    • 3
  1. 1.Division of Experimental Imaging, Department of Diagnostic and Interventional RadiologyUniversity Hospital FrankfurtFrankfurtGermany
  2. 2.Department of Diagnostic and Interventional RadiologyUniversity Hospital FrankfurtFrankfurtGermany
  3. 3.Department of Radiology and Radiological ScienceMedical University of South CarolinaCharlestonUSA
  4. 4.Department of Biomedical Sciences and Morphological and Functional ImagingUniversity Hospital MessinaMessinaItaly

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