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
- Sensitivity using original dose (2 mSv) [ Time Frame: 2 months ]
- Sensitivity at original dose (2 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist [ Time Frame: 2 months ]