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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.
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.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Suspected appendicitis | Patients who are suspected as having acute appendicitis |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| 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. |
| Measure | Description | Time Frame |
|---|---|---|
| Diagnostic performance at original dose (2 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist | The pooled area under curve (AUC) from three radiologists | 2 months |
| Diagnostic performance at 75% dose (1.5 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist | The pooled AUC from three radiologists | 1 months |
| Diagnostic performance at 50% dose (1.0 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist | *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 | 8 months |
| Diagnostic performance at 25% dose (0.5 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist | *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 | 14 months |
| Measure | Description | Time Frame |
|---|---|---|
| Sensitivity at original dose (2 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist | 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 months |
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Inclusion Criteria:
Exclusion Criteria:
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Emergency department visit with suspected symptoms and signs of acute appendicitis.
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| Name | Affiliation | Role |
|---|---|---|
| Ji Hoon Park, MD | Seoul National University Bundang Hospital | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Seoul National University Bunadang Hospital | Seongnam-si | Gyeonggi-do | 463-707 | South Korea |
| Type | Date | Date Unknown |
|---|---|---|
| Release | Dec 13, 2018 | |
| Unrelease | Dec 16, 2018 | |
| Release | Dec 16, 2018 | |
| Reset | Mar 27, 2019 |
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| Release Date | Unrelease Date | Unrelease Date Unknown | Reset Date | MCP Release Number |
|---|---|---|---|---|
| Dec 13, 2018 | Dec 16, 2018 | |||
| Dec 16, 2018 |
| ID | Term |
|---|---|
| D001064 | Appendicitis |
| ID | Term |
|---|---|
| D059413 | Intraabdominal Infections |
| D007239 | Infections |
| D005759 | Gastroenteritis |
| D005767 | Gastrointestinal Diseases |
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|
| Specificity at original dose (2 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist |
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 months |
| Sensitivity at 75% dose (1.5 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist | 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. | 1 month |
| Specificity at 75% dose (1.5 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist | 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. | 1 month |
| Sensitivity at 50% dose (1.0 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist | 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 months |
| Specificity at 50% dose (1.0 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist | 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 months |
| Sensitivity at 25% dose (0.5 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist | 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. | 14 months |
| Specificity at 25% dose (0.5 mSv) using 5-grade Likert score for the likelihood of appendicitis assigned by each radiologist | 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. | 14 months |
| Diagnostic confidence in diagnosing and ruling out appendicitis at original CT: the likelihood score for appendicitis | Likelihood score for appendicitis in patients confirmed as having appendicitis Likelihood score for appendicitis in patients confirmed as not having appendicitis | 2 months |
| Diagnostic confidence in diagnosing and ruling out appendicitis at 75%-dose CT: the likelihood score for appendicitis | Likelihood score for appendicitis in patients confirmed as having appendicitis Likelihood score for appendicitis in patients confirmed as not having appendicitis | 1 month |
| Diagnostic confidence in diagnosing and ruling out appendicitis at 50%-dose CT: the likelihood score for appendicitis | Likelihood score for appendicitis in patients confirmed as having appendicitis Likelihood score for appendicitis in patients confirmed as not having appendicitis | 8 month |
| Diagnostic confidence in diagnosing and ruling out appendicitis at 25%-dose CT: the likelihood score for appendicitis | Likelihood score for appendicitis in patients confirmed as having appendicitis Likelihood score for appendicitis in patients confirmed as not having appendicitis | 14 month |
| Diagnostic confidence in diagnosing and ruling out appendicitis at original CT: normal appendix visualization rate | The frequency of normal appendix visualization at CT | 2 month |
| Diagnostic confidence in diagnosing and ruling out appendicitis at 75%-dose CT: normal appendix visualization rate | The frequency of normal appendix visualization at CT | 1 month |
| Diagnostic confidence in diagnosing and ruling out appendicitis at 50%-dose CT: normal appendix visualization rate | The frequency of normal appendix visualization at CT | 8 months |
| Diagnostic confidence in diagnosing and ruling out appendicitis at 25%-dose CT: normal appendix visualization rate | The frequency of normal appendix visualization at CT | 14 months |
| Diagnostic confidence in diagnosing and ruling out appendicitis at original CT: indeterminate CT interpretation | The frequency of indeterminate CT interpretation (grade 3) | 2 months |
| Diagnostic confidence in diagnosing and ruling out appendicitis at 75%-dose CT: indeterminate CT interpretation | The frequency of indeterminate CT interpretation (grade 3) | 1 month |
| Diagnostic confidence in diagnosing and ruling out appendicitis at 50%-dose CT: indeterminate CT interpretation | The frequency of indeterminate CT interpretation (grade 3) | 8 months |
| Diagnostic confidence in diagnosing and ruling out appendicitis at 25%-dose CT: indeterminate CT interpretation | The frequency of indeterminate CT interpretation (grade 3) | 14 months |
| Alternative diagnoses at original CT: the radiologists will record possible alternative diagnosis if the patients are presumed to be not having appendicitis | The numbers of important alternative diagnoses established | 2 months |
| Alternative diagnoses at 75%-dose CT: the radiologists will record possible alternative diagnosis if the patients are presumed to be not having appendicitis | The numbers of important alternative diagnoses established | 1 month |
| Alternative diagnoses at 50%-dose CT: the radiologists will record possible alternative diagnosis if the patients are presumed to be not having appendicitis | The numbers of important alternative diagnoses established | 8 months |
| Alternative diagnoses at 25%-dose CT: the radiologists will record possible alternative diagnosis if the patients are presumed to be not having appendicitis | The numbers of important alternative diagnoses established | 14 months |
| Mar 27, 2019 |
| D004066 |
| Digestive System Diseases |
| D002429 | Cecal Diseases |
| D007410 | Intestinal Diseases |