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NCT Number: NCT01925014

Low vs. Standard Dose CT for Appendicitis Trial

To determine whether low-dose (LD) CT is noninferior to standard-dose (SD) computed tomography (CT) as the first-line imaging test in adolescents and young adults in regard to negative appendectomy rate (NAR).

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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

Interventional

Phase

Not applicable

Primary location

Kangwon National University Hospital, Chuncheon, Gangwon-do, South Korea

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About this study

  • Acute appendicitis is a very common disease. Many patients are adolescents or young adults.
  • CT is the current standard imaging test for the diagnosis of appendicitis.
  • In recent years, the awareness of carcinogenic risk associated with CT radiation has increased.
  • According to a recent single-institutional randomized controlled trial, LD CT (employing a quarter of standard radiation dose) was found to be noninferior to SD CT with respect to NARs in adolescents and young adults with suspected appendicitis.
  • However, LD CT is not yet widely accepted.
  • To establish LD CT as the first-line imaging test, a multi-institutional study is needed to confirm the generalizability of the prior single-institutional study.

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

  • Emergency department visit with suspected symptoms and signs of acute appendicitis
  • Intravenous contrast-enhanced computed tomography examination requested due to suspicion of appendicitis
  • Willing to provide telephone or cell phone numbers for follow-up
  • Signed informed consent provided prior to study entry

Exclusion criteria

  • Prior cross-sectional imaging tests to evaluate the presenting symptoms and signs
  • Prior history of surgical removal of the appendix

Treatment and study plan

Diagnostic CT with low-dose radiation

Diagnostic Test

Effective dose is aimed at approximately 2 millisievert (mSv) in an average patient.

Other names: Low-dose CT

Diagnostic CT with standard-dose radiation

Diagnostic Test

Effective dose is aimed at approximately 8 millisievert (or less) in an average patient.

Other names: Standard-dose CT

Primary outcomes

  1. Negative Appendectomy Rate

    Time frame: 1 week after surgery

    Negative appendectomy rate was defined as the percentage of negative (unnecessary) appendectomies among all non-incidental appendectomies. As a secondary analysis, negative appendectomy rate in an alternative definition was calculated by excluding cases with appendiceal neoplasms without superimposed appendicitis, as appendectomy would be clinically necessary in such patients. Any surgery performed for the treatment of presumed appendicitis was counted as non-incidental appendectomy, even though the surgical procedures were more extensive than simple appendectomy (e.g., ileocectomy).

Secondary outcomes

  1. Appendiceal Perforation Rate

    Time frame: 1 week after surgery

    The percentage of perforated appendicitis among confirmed appendicitis cases.

  2. Number of Appendectomies

    Time frame: 3 months after CT

    Appendectomy rate. The percentage of appendectomies among all randomized cases.

  3. Number of Negative Appendectomies

    Time frame: 1 week after surgery

    The percentage of negative appendectomies among all randomized cases. In January, 2016, when more than 2000 patients were enrolled, the data and safety monitoring board noted a between-group imbalance in the number of appendectomies. Because of the concern that such an imbalance might potentially jeopardize the comparability for the prespecified endpoints, the study protocol was amended to adopt the following additional secondary endpoints, which were assessed among all randomly assigned patients: the number of appendectomies, number of negative appendectomies, prevalence of perforated appendicitis, and prevalence of non-perforated appendicitis.

  4. Prevalence of Perforated Appendicitis

    Time frame: 1 week after surgery

    The percentage (i.e., prevalence) of perforated appendicitis among all randomized cases. In January, 2016, when more than 2000 patients were enrolled, the data and safety monitoring board noted a between-group imbalance in the number of appendectomies. Because of the concern that such an imbalance might potentially jeopardize the comparability for the prespecified endpoints, the study protocol was amended to adopt the following additional secondary endpoints, which were assessed among all randomly assigned patients: the number of appendectomies, number of negative appendectomies, prevalence of perforated appendicitis, and prevalence of non-perforated appendicitis.

  5. Prevalence of Non-perforated Appendicitis

    Time frame: 1 week after surgery

    The percentage (i.e., prevalence) of non-perforated appendicitis among all randomized cases. In January, 2016, when more than 2000 patients were enrolled, the data and safety monitoring board noted a between-group imbalance in the number of appendectomies. Because of the concern that such an imbalance might potentially jeopardize the comparability for the prespecified endpoints, the study protocol was amended to adopt the following additional secondary endpoints, which were assessed among all randomly assigned patients: the number of appendectomies, number of negative appendectomies, prevalence of perforated appendicitis, and prevalence of non-perforated appendicitis.

  6. Need for Additional Imaging Test(s)

    Time frame: 1 week after CT

    The proportion of patients requiring additional imaging test(s) in order to diagnose or rule out appendicitis.

  7. Delay in Patient Disposition

    Time frame: 3 months after CT

    • The interval from CT acquisition to appendectomy in patients undergoing appendectomy. Interval appendectomies following percutaneous abscess drainage and/or medical treatment were not included in this analysis.
    • The interval from CT acquisition to hospital discharge in patients not undergoing surgery.

  8. Length of Hospital Stay Associated With Appendectomy

    Time frame: 3 months after CT

    The interval from CT acquisition to hospital discharge after appendectomy.

  9. Diagnostic Performance of CT Reports - AUC

    Time frame: 3 months after CT

    • Area under the receiver-operating-characteristic curve (AUC).

  10. Diagnostic Performance of CT Reports - Sensitivity and Specificity

    Time frame: 3 months after CT

    • Diagnostic sensitivity and specificity: the 5-grade likelihood scores for appendicitis were collapsed into binary responses with a decision threshold of a score ≥ 3 as positive for the diagnosis.
    • Sensitivity is a proportion of the positive test among the patient confirmed as having appendicitis.
    • Specificity is a proportion of the negative test among the patient confirmed as not having appendicitis.

  11. Diagnostic Confidence in Diagnosing and Ruling Out Appendicitis: Likelihood Score for Appendicitis

    Time frame: 3 months after CT

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

    Grade 1 denotes appendicitis definitely absent; grade 2, appendicitis probably absent; grade 3, indeterminate for the presence of appendicitis; grade 4, appendicitis probably present; and grade 5, appendicitis definitely present.

  12. Diagnostic Confidence in Diagnosing and Ruling Out Appendicitis: Indeterminate Interpretation (Grade 3)

    Time frame: 3 months after CT

    The frequency of indeterminate CT interpretation (grade 3). Grade 1 denotes appendicitis definitely absent; grade 2, appendicitis probably absent; grade 3, indeterminate for the presence of appendicitis; grade 4, appendicitis probably present; and grade 5, appendicitis definitely present.

  13. Diagnostic Confidence in Ruling Out Appendicitis: Normal Appendix Visualization

    Time frame: 3 months after CT

    The frequency of normal appendix visualization at CT. Grade 0 denotes appendix not identified; grade 1, unsure or partly visualized; and grade 2, clearly and entirely visualized.

  14. Diagnosis of Appendiceal Perforation at CT

    Time frame: 3 months after CT

    • Diagnostic sensitivity: the number of correct detections of the perforation divided by the number of cases of perforated appendicitis.
    • Diagnostic specificity: the number of correct ruling out the perforation divided by the number of cases of appendicitis without perforation.

Sponsors and collaborators

Lead sponsor

Kyoung Ho Lee, MD

Other

Collaborators

  • Ministry of Health & Welfare, Korea
  • Radiology Imaging Network of Korea for Clinical Research
  • Seoul National University Bundang Hospital
  • The LOCAT Group

Registry information

Official study title

A Multi-institutional Trial Comparing Clinical Outcomes Following Low- vs. Standard-dose Abdominal CT as the First-line Imaging Test in Adolescents and Young Adults With Suspected Acute Appendicitis

Acronym: LOCAT

Important dates

Study start
2013
Primary completion
2016
Study completion
2017
First posted
Aug 19, 2013
Registry last updated
Jan 31, 2019

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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