Low vs. Standard Dose CT for Appendicitis Trial (LOCAT)

August 21, 2018 updated by: Kyoung Ho Lee, MD

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

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).

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

  • 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.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
3074

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Korea, Republic of
      • Daegu, Korea, Republic of, 700-712
        • Keimyung University Dongsan Medical Center
      • Gwangju, Korea, Republic of, 501-757
        • Chonnam National University Hospital
      • Iksan, Korea, Republic of, 570-711
        • Wonkwang University School of Medicine & Hospital
      • Incheon, Korea, Republic of, 405-760
        • Gachon University Gil Medical Center
      • Jeju City, Korea, Republic of, 690-767
        • Jeju National University Hospital
      • Seoul, Korea, Republic of, 110-744
        • Seoul National University Hospital
      • Seoul, Korea, Republic of, 156-755
        • Chung-Ang University Hospital
      • Seoul, Korea, Republic of, 152-703
        • Korea University Guro Hospital
      • Seoul, Korea, Republic of, 120-752
        • Severance Hospital
      • Seoul, Korea, Republic of, 150-950
        • Hallym University Kangnam Sacred Heart Hospital
      • Seoul, Korea, Republic of, 110-746
        • Kangbuk Samsung Hospital
      • Seoul, Korea, Republic of, 137-701
        • The Catholic University of Korea, College of Medicine, Seoul St. Mary's Hospital
      • Seoul, Korea, Republic of, 140-887
        • Soonchunhyang University Seoul Hospital
    • Gangwon
      • Chuncheon, Gangwon, Korea, Republic of, 200-722
        • Kangwon National University Hospital
    • Gyeonggi
      • Ansan, Gyeonggi, Korea, Republic of, 425-707
        • Korea University Ansan Hospital
      • Anyang, Gyeonggi, Korea, Republic of, 431-070
        • Hallym University Sacred Heart Hospital
      • Bucheon, Gyeonggi, Korea, Republic of, 420-767
        • Soonchunhyang University Bucheon Hospital
      • Sanbon, Gyeonggi, Korea, Republic of, 435-040
        • Wonkwang University Sanbon Hospital
      • Seongnam, Gyeonggi, Korea, Republic of, 463-707
        • Seoul National University Bundang Hospital
      • Seongnam, Gyeonggi, Korea, Republic of, 463-774
        • Daejin Medical Center, Bundang Jesaeng General Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

15 years to 44 years (ADULT, CHILD)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: DIAGNOSTIC
  • Allocation: RANDOMIZED
  • Interventional Model: PARALLEL
  • Masking: DOUBLE

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
EXPERIMENTAL: Low-dose CT
Diagnostic CT with low-dose radiation
Diagnostic test: Diagnostic CT with low-dose radiation
Effective dose is aimed at approximately 2 millisievert (mSv) in an average patient.
Other Names:
  • Low-dose CT
ACTIVE_COMPARATOR: Standard-dose CT
Diagnostic CT with standard-dose radiation
Diagnostic test: Diagnostic CT with standard-dose radiation
Effective dose is aimed at approximately 8 millisievert (or less) in an average patient.
Other Names:
  • Standard-dose CT

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
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).
1 week after surgery

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Appendiceal Perforation Rate
Time Frame: 1 week after surgery
The percentage of perforated appendicitis among confirmed appendicitis cases.
1 week after surgery
Number of Appendectomies
Time Frame: 3 months after CT
Appendectomy rate. The percentage of appendectomies among all randomized cases.
3 months after CT
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.
1 week after surgery
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.
1 week after surgery
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.
1 week after surgery
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.
1 week after CT
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.
3 months after CT
Length of Hospital Stay Associated With Appendectomy
Time Frame: 3 months after CT
The interval from CT acquisition to hospital discharge after appendectomy.
3 months after CT
Diagnostic Performance of CT Reports - AUC
Time Frame: 3 months after CT
- Area under the receiver-operating-characteristic curve (AUC).
3 months after CT
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.
3 months after CT
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.
3 months after CT
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.
3 months after CT
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.
3 months after CT
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.
3 months after CT

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Kyoung Ho Lee, MD

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Seoul National University Bundang Hospital
Ministry of Health & Welfare, Korea
Radiology Imaging Network of Korea for Clinical Research
The LOCAT Group

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Chair: Kyoung Ho Lee, MD, Seoul National University Bundang Hospital
  • Study Director: Kyuseok Kim, MD, Seoul National University Bundang Hospital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (ACTUAL)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
December 1, 2013

Primary Completion (ACTUAL)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 1, 2016

Study Completion (ACTUAL)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
February 1, 2017

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
August 15, 2013

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 16, 2013

First Posted (ESTIMATE)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
August 19, 2013

Study Record Updates

Last Update Posted (ACTUAL)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
January 31, 2019

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 21, 2018

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
August 1, 2018

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • LOCAT

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

The LOCAT Group has an active standpoint for sharing the LOCAT data, which is in line with the proposal from the International Committee of Medical Journal Editors. The LOCAT Group will share de-identified individual-participant data underlying the main LOCAT results no later than 6 months after the publication of the results. The data will be kept in a publicly available website and freely available to anyone upon request.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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