CT Dose Simulation Study for Appendicitis

Completed

• Conditions: Appendicitis
• Interventions: Radiation: CT

• Registration Number: NCT02556983
• Lead Sponsor: Seoul National University Bundang Hospital

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 Description

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.

Study Timeline

• Study Start: 2015-08
• Study First Submitted: 2015-09-18
• Study First Submitted QC: 2015-09-20
• Study First Posted: 2015-09-22
• Primary Completion: 2017-02
• Study Completion: 2017-03
• Status Verified: 2017-04
• Last Update Submitted: 2017-04-11
• Last Update Posted: 2017-04-12

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 30

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

Read More

Exclusion Criteria

• having contraindications of intravenous contrast agent

Read More

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
Suspected appendicitis	CT	Patients who are suspected as having acute appendicitis

Primary Outcome Measures

Name	Time	Method
Diagnostic performance at original dose (2 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist	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	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	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	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 Outcome Measures

Name	Time	Method
Diagnostic confidence in diagnosing and ruling out appendicitis at original CT: the likelihood score for appendicitis	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	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	8 month	Likelihood score for appendicitis in patients confirmed as having appendicitis Likelihood score for appendicitis in patients confirmed as not having appendicitis
Sensitivity at original dose (2 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist	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	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	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	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 25% dose (0.5 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist	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 original dose (2 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist	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 25% dose (0.5 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist	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 75% dose (1.5 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist	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.
Diagnostic confidence in diagnosing and ruling out appendicitis at original CT: normal appendix visualization rate	2 month	The frequency of normal appendix visualization at CT
Diagnostic confidence in diagnosing and ruling out appendicitis at 25%-dose CT: normal appendix visualization rate	14 months	The frequency of normal appendix visualization at CT
Diagnostic confidence in diagnosing and ruling out appendicitis at 75%-dose CT: indeterminate CT interpretation	1 month	The frequency of indeterminate CT interpretation (grade 3)
Diagnostic confidence in diagnosing and ruling out appendicitis at original CT: indeterminate CT interpretation	2 months	The frequency of indeterminate CT interpretation (grade 3)
Diagnostic confidence in diagnosing and ruling out appendicitis at 25%-dose CT: the likelihood score for appendicitis	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 75%-dose CT: normal appendix visualization rate	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	8 months	The frequency of normal appendix visualization at CT
Alternative diagnoses at 25%-dose CT: the radiologists will record possible alternative diagnosis if the patients are presumed to be not having appendicitis	14 months	The numbers of important alternative diagnoses established
Diagnostic confidence in diagnosing and ruling out appendicitis at 50%-dose CT: indeterminate CT interpretation	8 months	The frequency of indeterminate CT interpretation (grade 3)
Diagnostic confidence in diagnosing and ruling out appendicitis at 25%-dose CT: indeterminate CT interpretation	14 months	The frequency of indeterminate CT interpretation (grade 3)
Alternative diagnoses at original CT: the radiologists will record possible alternative diagnosis if the patients are presumed to be not having appendicitis	2 months	The numbers of important alternative diagnoses established
Alternative diagnoses at 50%-dose CT: the radiologists will record possible alternative diagnosis if the patients are presumed to be not having appendicitis	8 months	The numbers of important alternative diagnoses established
Alternative diagnoses at 75%-dose CT: the radiologists will record possible alternative diagnosis if the patients are presumed to be not having appendicitis	1 month	The numbers of important alternative diagnoses established

Trial Locations

Locations (1)

Seoul National University Bunadang Hospital; 🇰🇷 Seongnam-Si, Gyeonggi-do, Korea, Republic of