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Completed

NCT Number: NCT02556983

CT Dose Simulation Study for Appendicitis

The study will explore CT radiation dose as low as reasonably achievable in diagnosing acute appendicitis, by using of dose simulation technique and iterative reconstruction.

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Key information

Conditions

Appendicitis Cecal Diseases Digestive System Diseases Gastroenteritis Gastrointestinal Diseases Infections Intestinal Diseases Intraabdominal Infections

Age range

15 year–44 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Seoul National University Bunadang Hospital

Seongnam-si, Gyeonggi-do, 463-707, South Korea

About this study

Three sequential non-inferiority tests are planned. First, three readers will review the original 2-mSv images. Second, the readers will review the 75%-dose images. After the readers review the 75%-dose images and before the readers reviewed the 50%-dose images, the non-inferiority of 75% dose to the original dose will be tested. If the non-inferiority is not accepted, the study will be terminated with the conclusion of 2 mSv as the lowest acceptable dose. If the non-inferiority is accepted, the study will be continue to the next step. In the same manner, the readers will review the next lower-dose images (50% and then 25%), and then the noninferiority will be tested against the original dose.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 18-44 years of age.
  • Emergency department visit with suspected symptoms and signs of acute appendicitis
  • Intravenous contrast-enhanced computed tomography examination requested due to suspicion of appendicitis

Exclusion criteria

  • having contraindications of intravenous contrast agent

Treatment and study plan

CT

Radiation

Contrast-enhanced CT images of the abdomen and pelvis will be obtained during the portal venous phase using a 256-channel CT system (Philips Healthcare, Cleveland, OH). The target median dose-length product (DLP) is 130 mGy·cm, which corresponded to an effective dose of 2 mSv with a conversion factor of 0.015 mSv·mGy-1·cm-1. The radiation output was automatically adjusted according to the individual patient's body size.

Primary outcomes

  1. Diagnostic performance at original dose (2 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist

    Time frame: 2 months

    The pooled area under curve (AUC) from three radiologists

  2. Diagnostic performance at 75% dose (1.5 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist

    Time frame: 1 months

    The pooled AUC from three radiologists

  3. Diagnostic performance at 50% dose (1.0 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist

    Time frame: 8 months

    *The analysis of 50%-dose CT images will be performed only if non-inferiority of 75%-dose CT to the original CT is proven in terms of the pooled AUC.

    The pooled AUC from three radiologists

  4. Diagnostic performance at 25% dose (0.5 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist

    Time frame: 14 months

    *The analysis of 25%-dose CT images will be performed only if non-inferiority of 50%-dose CT is proven to the original CT in terms of the pooled AUC.

    The pooled AUC from three radiologists

Secondary outcomes

  1. Sensitivity at original dose (2 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist

    Time frame: 2 months

    For calculation of sensitivity and specificity, the 5-grade scores are collapsed into binary responses with a decision threshold of a score ≥ 3 as positive for the diagnosis.

  2. Specificity at original dose (2 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist

    Time frame: 2 months

    For calculation of sensitivity and specificity, the 5-grade scores are collapsed into binary responses with a decision threshold of a score ≥ 3 as positive for the diagnosis.

  3. Sensitivity at 75% dose (1.5 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist

    Time frame: 1 month

    For calculation of sensitivity and specificity, the 5-grade scores are collapsed into binary responses with a decision threshold of a score ≥ 3 as positive for the diagnosis.

  4. Specificity at 75% dose (1.5 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist

    Time frame: 1 month

    For calculation of sensitivity and specificity, the 5-grade scores are collapsed into binary responses with a decision threshold of a score ≥ 3 as positive for the diagnosis.

  5. Sensitivity at 50% dose (1.0 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist

    Time frame: 8 months

    For calculation of sensitivity and specificity, the 5-grade scores are collapsed into binary responses with a decision threshold of a score ≥ 3 as positive for the diagnosis.

  6. Specificity at 50% dose (1.0 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist

    Time frame: 8 months

    For calculation of sensitivity and specificity, the 5-grade scores are collapsed into binary responses with a decision threshold of a score ≥ 3 as positive for the diagnosis.

  7. Sensitivity at 25% dose (0.5 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist

    Time frame: 14 months

    For calculation of sensitivity and specificity, the 5-grade scores are collapsed into binary responses with a decision threshold of a score ≥ 3 as positive for the diagnosis.

  8. Specificity at 25% dose (0.5 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist

    Time frame: 14 months

    For calculation of sensitivity and specificity, the 5-grade scores are collapsed into binary responses with a decision threshold of a score ≥ 3 as positive for the diagnosis.

  9. Diagnostic confidence in diagnosing and ruling out appendicitis at original CT: the likelihood score for appendicitis

    Time frame: 2 months

    Likelihood score for appendicitis in patients confirmed as having appendicitis Likelihood score for appendicitis in patients confirmed as not having appendicitis

  10. Diagnostic confidence in diagnosing and ruling out appendicitis at 75%-dose CT: the likelihood score for appendicitis

    Time frame: 1 month

    Likelihood score for appendicitis in patients confirmed as having appendicitis Likelihood score for appendicitis in patients confirmed as not having appendicitis

  11. Diagnostic confidence in diagnosing and ruling out appendicitis at 50%-dose CT: the likelihood score for appendicitis

    Time frame: 8 month

    Likelihood score for appendicitis in patients confirmed as having appendicitis Likelihood score for appendicitis in patients confirmed as not having appendicitis

  12. Diagnostic confidence in diagnosing and ruling out appendicitis at 25%-dose CT: the likelihood score for appendicitis

    Time frame: 14 month

    Likelihood score for appendicitis in patients confirmed as having appendicitis Likelihood score for appendicitis in patients confirmed as not having appendicitis

  13. Diagnostic confidence in diagnosing and ruling out appendicitis at original CT: normal appendix visualization rate

    Time frame: 2 month

    The frequency of normal appendix visualization at CT

  14. Diagnostic confidence in diagnosing and ruling out appendicitis at 75%-dose CT: normal appendix visualization rate

    Time frame: 1 month

    The frequency of normal appendix visualization at CT

  15. Diagnostic confidence in diagnosing and ruling out appendicitis at 50%-dose CT: normal appendix visualization rate

    Time frame: 8 months

    The frequency of normal appendix visualization at CT

  16. Diagnostic confidence in diagnosing and ruling out appendicitis at 25%-dose CT: normal appendix visualization rate

    Time frame: 14 months

    The frequency of normal appendix visualization at CT

  17. Diagnostic confidence in diagnosing and ruling out appendicitis at original CT: indeterminate CT interpretation

    Time frame: 2 months

    The frequency of indeterminate CT interpretation (grade 3)

  18. Diagnostic confidence in diagnosing and ruling out appendicitis at 75%-dose CT: indeterminate CT interpretation

    Time frame: 1 month

    The frequency of indeterminate CT interpretation (grade 3)

  19. Diagnostic confidence in diagnosing and ruling out appendicitis at 50%-dose CT: indeterminate CT interpretation

    Time frame: 8 months

    The frequency of indeterminate CT interpretation (grade 3)

  20. Diagnostic confidence in diagnosing and ruling out appendicitis at 25%-dose CT: indeterminate CT interpretation

    Time frame: 14 months

    The frequency of indeterminate CT interpretation (grade 3)

  21. Alternative diagnoses at original CT: the radiologists will record possible alternative diagnosis if the patients are presumed to be not having appendicitis

    Time frame: 2 months

    The numbers of important alternative diagnoses established

  22. Alternative diagnoses at 75%-dose CT: the radiologists will record possible alternative diagnosis if the patients are presumed to be not having appendicitis

    Time frame: 1 month

    The numbers of important alternative diagnoses established

  23. Alternative diagnoses at 50%-dose CT: the radiologists will record possible alternative diagnosis if the patients are presumed to be not having appendicitis

    Time frame: 8 months

    The numbers of important alternative diagnoses established

  24. Alternative diagnoses at 25%-dose CT: the radiologists will record possible alternative diagnosis if the patients are presumed to be not having appendicitis

    Time frame: 14 months

    The numbers of important alternative diagnoses established

Sponsors and collaborators

Lead sponsor

Seoul National University Bundang Hospital

Other

Registry information

Official study title

Optimizing the Radiation Dose for CT Imaging With Iterative Reconstruction in Diagnosing Acute Appendicitis: Dose Simulation Study

Important dates

Study start
2015
Primary completion
2017
Study completion
2017
First posted
Sep 22, 2015
Registry last updated
Apr 12, 2017

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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