European Radiology

, Volume 28, Issue 5, pp 1826–1834 | Cite as

Can We Perform CT of the Appendix with Less Than 1 mSv? A De-escalating Dose-simulation Study

  • Ji Hoon Park
  • Jong-June Jeon
  • Sung Soo Lee
  • Amar C. Dhanantwari
  • Ji Ye Sim
  • Hae Young Kim
  • Kyoung Ho Lee
Computed Tomography
  • 116 Downloads

Abstract

Objectives

To systematically explore the lowest reasonably achievable radiation dose for appendiceal CT using an iterative reconstruction (IR) in young adults.

Methods

We prospectively included 30 patients who underwent 2.0-mSv CT for suspected appendicitis. From the helical projection data, 1.5-, 1.0- and 0.5-mSv CTs were generated using a low-dose simulation tool and the knowledge-based IR. We performed step-wise non-inferiority tests sequentially comparing 2.0-mSv CT with each of 1.5-, 1.0- and 0.5-mSv CT, with a predetermined non-inferiority margin of 0.06. The primary end point was the pooled area under the receiver-operating-characteristic curve (AUC) for three abdominal and three non-abdominal radiologists.

Results

For the abdominal radiologists, the non-inferiorities of 1.5-, 1.0- and 0.5-mSv CT to 2.0-mSv CT were sequentially accepted [pooled AUC difference: 2.0 vs. 0.5 mSv, 0.017 (95% CI: -0.016, 0.050)]. For the non-abdominal radiologists, the non-inferiorities of 1.5- and 1.0-mSv CT were accepted; however, the non-inferiority of 0.5-mSv CT could not be proved [pooled AUC difference: 2.0 vs. 1.0 mSv, -0.017 (-0.070, 0.035) and 2.0 vs. 0.5 mSv, 0.045 (-0.071, 0.161)].

Conclusion

The 1.0-mSv appendiceal CT was non-inferior to 2.0-mSv CT in terms of diagnostic performance for both abdominal and non-abdominal radiologists; 0.5-mSv appendiceal CT was non-inferior only for abdominal radiologists.

Key points

• For both abdominal and non-abdominal radiologists, 1.0-mSv appendiceal CT could be feasible.

• The 0.5-mSv CT was non-inferior to 2.0-mSv CT only for expert abdominal radiologists.

• Reader experience is an important factor affecting diagnostic impairment by low-dose CT.

Keywords

Appendicitis Prospective studies Tomography, X-ray computed ROC curve Sensitivity and specificity 

Abbreviations

IR

Iterative reconstruction

AUC

Area under the receiver-operating-characteristic curve

Notes

Acknowledgements

We thank Kyung Hwa Han in Yonsei University College of Medicine for her advice on sample size calculation.

Compliance with ethical standards

Guarantor

The scientific guarantor of this publication is Kyoung Ho Lee.

Conflict of interest

One of the co-authors (Amar C. Dhanantwari) is an employee of Philips. He contributed to imaging processing regarding radiation dose simulation and manuscript editing, but did not interfere with the medical interpretation proposed in this study. Otherwise, there are no conflicts of interest to declare.

Statistics and biometry

One of the authors has significant statistical expertise.

Informed consent

Written informed consent was obtained from all subjects (patients) in this study.

Ethical approval

Institutional Review Board approval was obtained.

Methodology

• prospective

• diagnostic study

• performed at one institution

Supplementary material

330_2017_5159_MOESM1_ESM.docx (1.2 mb)
ESM 1 (DOCX 1267 kb)

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Copyright information

© European Society of Radiology 2017

Authors and Affiliations

  • Ji Hoon Park
    • 1
  • Jong-June Jeon
    • 2
  • Sung Soo Lee
    • 1
  • Amar C. Dhanantwari
    • 3
  • Ji Ye Sim
    • 4
  • Hae Young Kim
    • 1
  • Kyoung Ho Lee
    • 1
    • 5
  1. 1.Department of RadiologySeoul National University Bundang HospitalSeongnam-siKorea
  2. 2.Department of StatisticsUniversity of SeoulSeoulKorea
  3. 3.CT/AMI Clinical ScienceClevelandUSA
  4. 4.Department of RadiologyHanil General HospitalSeoulKorea
  5. 5.Program in Biomedical Radiation Sciences, Department of Transdisciplinary StudiesGraduate School of Convergence Science and Technology Seoul National UniversitySeoulKorea

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