Effective Withdrawal Time and Adenoma Detection Rate

September 3, 2025 updated by: Dr. Lui Ka-Luen, The University of Hong Kong

Prospective Evaluation of Artificial Intelligence-assisted Monitoring of Effective Withdrawal Time on Adenoma Detection

This study prospectively evaluated the role of EWT versus SWT on adenoma detection rate (ADR) and other key quality metrics. In this prospective single-center study, patients undergoing colonoscopy were enrolled. EWT was calculated in real-time using an AI system with endoscopists blinded to the results. We performed multivariable analyses to assess the association of EWT and SWT with binary (e.g., ADR) and count outcomes (e.g., adenoma per colonoscopy [APC]), after adjusting for patient and procedural characteristics.

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

This was a prospective, single-center observational study designed to determine if an AI-powered metric, Effective Withdrawal Time (EWT), is a superior predictor of colonoscopy quality compared to the traditional Standard Withdrawal Time (SWT). All colonoscopies were performed by qualified endoscopists using high-definition white light video scopes. During the procedure, the scope is first advanced to the start of the large intestine (the cecum). The critical examination phase-the withdrawal-begins as the endoscopist slowly pulls the scope back out, meticulously inspecting the colon lining for abnormalities like polyps. It is during this withdrawal that the key metrics were measured. While SWT is a simple duration timed manually, the AI-measured EWT specifically quantifies the time of high-quality mucosal inspection, automatically excluding periods when the camera view is blurry, obscured, or moving too quickly. A crucial aspect of the methodology was that the endoscopists were blinded to the live EWT measurements to prevent the Hawthorne effect, where individuals alter their behaviour because they are being monitored. The study enrolled adults aged 40 and over, excluding patients with conditions that could confound the findings. The primary goal was to assess the independent impact of EWT on the Adenoma Detection Rate (ADR), a key benchmark based on the detection and removal of precancerous polyps for analysis. To achieve this, researchers used multivariable regression models to isolate EWT's effect from other variables and employed correlation tests to statistically compare whether EWT had a stronger relationship with detection quality than SWT

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.
Observational

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.
193

Contacts and Locations

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

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.
  • Name: Ka Luen Thomas Lui
  • Phone Number: +852 97360997
  • Email: tkllui@hku.hk

Study Locations

  • Hong Kong
      • Hong Kong, Hong Kong
        • Queen Mary Hospital, The University of Hong Kong

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

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

All patient will be recruited in Queen Mary Hospital, Hong Kong, China

Description

Inclusion Criteria: All adult patients, aged 40 or above, undergoing outpatient colonoscopy will be recruited

Exclusion Criteria:

  • history of inflammatory bowel disease
  • history of colorectal cancer
  • previous bowel resection (apart from appendectomy)
  • Peutz-Jeghers syndrome, familial adenomatous polyposis or other polyposis syndromes
  • bleeding tendency or severe comorbid illnesses for which polypectomy is considered unsafe.
  • Cecum could not be intubated for various reasons
  • Poor bowel preparation with Boston Bowel Preparation Scale (BBPS) < 6

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

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
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.
AI group
AI monitoring of effective withdrawal time
Device: Endoscreen QC
Artificial intelligence monitoring of effective withdrawal time

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
Adenoma detection rates
Time Frame: During the colonoscopy
Adenoma detection rates
During the colonoscopy

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
Polyp detection rate
Time Frame: During that colonoscopy
Polyp detection rates of the colonoscopy
During that colonoscopy
Adenoma per colonoscopy
Time Frame: During colonoscopy
Adenoma per colonoscopy
During colonoscopy
Polyp per colonoscopy
Time Frame: During colonoscopy
Polyp per colonoscopy
During colonoscopy
Serrated lesion detection rate
Time Frame: During colonoscopy
Serrated lesion detection rates of that colonoscopy
During colonoscopy
Advanced adenoma detection rate
Time Frame: During colonoscopy
Advanced adenoma detection rates of that colonoscopy
During colonoscopy
Serrated lesion per colonoscopy
Time Frame: During colonoscopy
Serrated lesion per colonoscopy
During colonoscopy
Advanced adenoma per colonoscopy
Time Frame: During colonoscopy
Advanced adenoma per colonoscopy
During colonoscopy

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.
The University of Hong Kong

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.
  • Principal Investigator: Ka Luen Thomas Lui, The University of Hong Kong

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.
November 1, 2023

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.
September 30, 2024

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.
January 31, 2025

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).
September 20, 2023

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.
September 30, 2023

First Posted (Actual)

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.
October 2, 2023

Study Record Updates

Last Update Posted (Estimated)

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.
September 10, 2025

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.
September 3, 2025

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.
September 1, 2025

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.
  • AIeffectiveV3

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

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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