Clinical Trial: CT Dose Simulation Study for Appendicitis

Study Status: Completed
Recruit Status: Completed
Study Type: Observational

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

Brief Summary: 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.

Detailed Summary: 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.
Sponsor: Seoul National University Bundang Hospital

Current Primary Outcome:

  • 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
  • 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
  • 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

  • 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



Original Primary Outcome:

  • Diagnostic performance using original dose (2 mSv) [ Time Frame: 2 months ]

    The pooled area under curve (AUC) from three radiologists

    -using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist

  • Diagnostic performance using 75% dose (1.5 mSv) [ Time Frame: 1 months ]

    The pooled AUC from three radiologists

    -using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist

  • Diagnostic performance using 50% dose (1.0 mSv) [ 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

    -using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist

  • Diagnostic performance using 25% dose (0.5 mSv) [ 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

    -using

    Current Secondary Outcome:

    • 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.
    • 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.
    • 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.
    • 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.
    • 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.
    • 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.
    • 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.
    • 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.
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • Diagnostic confidence in diagnosing and ruling out appendicitis at 50%-dose CT: normal appendix visualization rate [ Time Frame: 8 months ]
      The freque

      Original Secondary Outcome:

      • Sensitivity using original dose (2 mSv) [ 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.
      • Specificity using original dose (2 mSv) [ 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.
      • Sensitivity using 75% dose (1.5 mSv) [ 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.
      • Specificity using 75% dose (1.5 mSv) [ 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.
      • Sensitivity using 50% dose (1.0 mSv) [ 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.
      • Specificity using 50% dose (1.0 mSv) [ 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.
      • Sensitivity using 25% dose (0.5 mSv) [ 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.
      • Specificity using 25% dose (0.5 mSv) [ 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.
      • 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
      • 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
      • 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
      • 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
      • 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
      • 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
      • 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
      • 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
      • 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)
      • Diagnostic confidence i

        Information By: Seoul National University Bundang Hospital

        Dates:
        Date Received: September 18, 2015
        Date Started: August 2015
        Date Completion:
        Last Updated: April 11, 2017
        Last Verified: April 2017