Virtual Colonoscopy Using Omnipaque as a Contrast Agent

Sponsor

Montefiore Medical Center (Other)

Overall Status

Recruiting

CT.gov ID

NCT04582500

Collaborator

GE Healthcare (Industry)

Enrollment

Location

18.5

Anticipated Duration (Months)

2.7

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

CT colonography (CTC) is a validated screening exam for colorectal cancer. The diagnostic accuracy of CTC depends on the quality of the bowel cleansing and contrast tagging of residual stool and fluid. New bowel preparation media for CTC should be assessed for their efficacy and for patient satisfaction. Iohexol is currently approved by the FDA for oral use for imaging of the gastrointestinal tract. A potential advantage of using iohexol for CTC is that low-and iso-osmolar oral contrast agents have fewer risks than hyperosmolar contrast agents, which make them ideal for use in all patients, especially those who are frail and/or have multiple co-morbidities. For example, hyperosmolar contrast agents that are accidentally aspirated into the lungs during ingestion may result in life-threatening acute pulmonary edema and severe chemical pneumonitis, which is not the case for low- and iso-osmolar contrast agents. It may even be safer to use low- or iso-osmolar contrast agents for patients undergoing CTC on the same day as their incomplete colonoscopy, since they are at risk for aspiration from being sedated for their colonoscopy. Additionally, unlike hyperosmolar contrast agents, low- and iso-osmolar contrast agents do not cause sudden and massive fluid shifts, thus eliminating the risk of dangerous electrolyte imbalances.

Condition or Disease	Intervention/Treatment	Phase
Colorectal Cancer	Drug: Iohexol

Detailed Description

Colorectal cancer is the third most common cancer and the second leading cause of cancer-related mortality in the United States when both sexes are combined. Given that the time interval between the appearance of a pre-malignant adenoma and its progression to invasive carcinoma is approximately 5.5 years for polyps >10 mm and 10-15 years for smaller polyps, colorectal cancer is an ideal disease for screening because there is sufficient time to detect and remove pre-malignant adenomas. However, even though screening has been shown to decrease colorectal cancer mortality, only about 60% of people over the age of 50 have had the recommended screening tests.

First introduced in 1994, computed tomography colonography (CTC) is a validated colorectal cancer screening exam by the American Cancer Society. It is a low-radiation dose CT scan of the colon that is performed after bowel preparation and gas insufflation of the colon. CTC has several advantages over optical colonoscopy including less invasiveness, no need for sedation, improved patient comfort, and the ability to identify extracolonic findings. The performance of CTC for polyp detection compares favorably to that of optical colonoscopy and CTC is rapidly gaining acceptance as a screening and diagnostic technique.

For accurate diagnosis in CTC, the colon must be adequately cleansed and any residual stool and fluid must be tagged so that they do not obscure polyps or masses. Patients often find bowel preparation to be the most onerous part of the screening process because it is inconvenient and uncomfortable. Many bowel preparations for CTC and optical colonoscopy require ingestion of large volumes of laxative solutions that can lead to nausea, abdominal pain and diarrhea. Additionally, for CTC, currently the most widely used tagging agents are hyperosmolar iodinated and barium based agents such as diatrizoate meglumine and diatrizoate sodium solution (Gastrografin; Bracco Diagnostics, Monroe Township, NJ), a hyperosmolar ionic iodinated contrast agent. These hyperosmolar agents can also lead to nausea, abdominal pain and diarrhea, and can even result in dangerous electrolyte balances from rapid fluid shifts. Changing the current bowel preparation regimen to improve patient comfort, convenience, and safety would most likely increase patient compliance with CTC.

Iohexol (Omnipaque; GE Healthcare, Milwaukee, WI) is a low-osmolar non-ionic iodinated contrast agent that is approved by the FDA for oral use. It is routinely used orally for CT scans of the abdomen and pelvis, and has been used experimentally in CTC. Iohexol is better tolerated by patients and has a better safety profile than hyperosmolar iodinated and barium based contrast agents.

Study Hypotheses

Oral iohexol in conjunction with a minimally cathartic agent results in adequate bowel preparation for CTC.
Oral iohexol provides effective tagging of residual stool and fluid in standard screening and diagnostic CTC and same-day CTC following incomplete optical colonoscopy.
Oral iohexol is well tolerated by patients in terms of taste, ease of preparation, and side effects.

Study Design

Study Type:

Observational

Anticipated Enrollment :

50 participants

Observational Model:

Cohort

Time Perspective:

Prospective

Official Title:

Low-osmolar Contrast Tagging in Minimal Cathartic CT Colonography

Actual Study Start Date :

Feb 15, 2021

Anticipated Primary Completion Date :

Aug 31, 2022

Anticipated Study Completion Date :

Aug 31, 2022

Arms and Interventions

Arm	Intervention/Treatment
patients undergoing CTC receiving iohexol Patients will be recruited from a pool scheduled to undergo screening or diagnostic CTC for clinical purposes. They will be given 50 ml of Iohexol as a oral contrast	Drug: Iohexol Iohexol (Omnipaque; GE Healthcare, Milwaukee, WI) is a low-osmolar non-ionic iodinated contrast agent that is approved by the FDA for oral use. It is routinely used orally for CT scans of the abdomen and pelvis, and has been used experimentally in CTC. Iohexol is better tolerated by patients and has a better safety profile than hyperosmolar iodinated and barium based contrast agents. Other Names: OMNIPAQUE

Arm

Intervention/Treatment

patients undergoing CTC receiving iohexol

Patients will be recruited from a pool scheduled to undergo screening or diagnostic CTC for clinical purposes. They will be given 50 ml of Iohexol as a oral contrast

Drug: Iohexol

Other Names:

OMNIPAQUE

Outcome Measures

Primary Outcome Measures

adequate bowel preparation [Within 3 business days of completing CTC]
Two experienced board-certified abdominal imaging radiologists trained in reading CTC will assess percent bowel preparation
Amount of residual fluid and stool [Within 3 business days of completing CTC]
Two experienced board-certified abdominal imaging radiologists trained in reading CTC will assess residual fluid in each of the six segments of the colon (cecum, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum)- Each segment will be scored as - 1 - none, 2 - <25%, 3 - 25-50%, 4: 50-75%, 5: >75%
Efficacy of residual fluid and stool [Within 3 business days of completing CTC]
Two experienced board-certified abdominal imaging radiologists trained in reading CTC will assess residual fluid in each of the six segments of the colon (cecum, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum)- Each segment will be scored as - 1 - none, 2 - <25%, 3 - 25-50%, 4: 50-75%, 5: >75%
Amount of colonic bubbles [Within 3 business days of completing CTC]
Two experienced board-certified abdominal imaging radiologists trained in reading CTC will assess residual fluid in each of the six segments of the colon (cecum, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum)- Each segment will be scored as - 1 - none, 2 - <25%, 3 - 25-50%, 4: 50-75%, 5: >75%
Attenuation of tagged fluid [Within 3 business days of completing CTC]
Two experienced board-certified abdominal imaging radiologists trained in reading CTC will assess residual fluid in each of the six segments of the colon (cecum, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum) It will be recorded in Hounsfield units from ROI of fluid in each segment
Patient Satisfaction [immediately after CTC]
Patient satisfaction with Omnipaque 350 as part of their bowel preparation regimen will be assessed with Likert scales in a questionnaire that patient will be asked to fill out after CTC.

Secondary Outcome Measures

Assessing Workflow of incomplete colonoscopies [through study completion, an average of 1 year]
A subset analysis on the workflow of incomplete colonoscopies will also be performed. Specifically those patients who have an incomplete colonoscopy and have a CTC the same day with the Omnipaque regimen and those patients who choose to reattempt or forgo Colorectal cancer screening until a later date. The time and resources between those patients who have CTC on the same-day with the Omnipaque regimen after incomplete colonoscopy and the other subset will be compared and determination of the effectiveness of both workflows will be made. This will be used to gauge the productivity for the site.

Eligibility Criteria

Criteria

Ages Eligible for Study:

18 Years and Older

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Yes

Inclusion Criteria:

age ≥18 years
able to provide written informed consent

Exclusion Criteria:

hypersensitivity to iodine-containing compounds,
pregnant or lactating,
diuretic therapy, and
enrollment in other clinical research trials involving investigational drugs

Contacts and Locations

Locations

	Site	City	State	Country	Postal Code
1	Montefiore Medical Center	Bronx	New York	United States	10467

Sponsors and Collaborators

Montefiore Medical Center
GE Healthcare

Investigators

Principal Investigator: Judy Yee, MD, FACR, Montefiore Medical Center

Study Documents (Full-Text)

None provided.

More Information

Publications

Responsible Party:

Montefiore Medical Center

ClinicalTrials.gov Identifier:

NCT04582500

Other Study ID Numbers:

2018-9791

First Posted:

Oct 9, 2020

Last Update Posted:

Mar 31, 2022

Last Verified:

Mar 1, 2022

Individual Participant Data (IPD) Sharing Statement:

Plan to Share IPD:

Studies a U.S. FDA-regulated Drug Product:

Yes

Studies a U.S. FDA-regulated Device Product:

Keywords provided by Montefiore Medical Center

Screening

Additional relevant MeSH terms:

Colorectal Neoplasms

Study Results

No Results Posted as of Mar 31, 2022