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Oral Iohexol for Fecal/Fluid Tagging for CT Colonography: A Study to Improve Image Quality by Preventing Colonic Bubbles

20 Years
Open (Enrolling)
Colorectal Neoplasms

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Trial Information

Oral Iohexol for Fecal/Fluid Tagging for CT Colonography: A Study to Improve Image Quality by Preventing Colonic Bubbles

CT colonography (CTC) is a recently developed radiological examination to find colorectal
neoplasia. Fecal/fluid tagging using oral administration of contrast is an essential
procedure for CTC. Iohexol, which has recently started being used as an agent for
fecal/fluid tagging, has great advantages as it has much more tolerable taste and much lower
rates of adverse effects such as clamping or diarrhea compared with traditionally used
Gastrografin/Gastroview. However, iohexol is frequently associated with an occurrence of a
lot of bubbles in the colon, which makes CTC interpretation more time-consuming and

Past experience in colonoscopy field suggests that simethicone, a safety-proven highly
inexpensive over-the-counter medicine, might resolve this issue. Given the fact that patient
convenience is an important factor for a successful CTC and the fact that time-intensive
nature of CTC interpretation is one of the major deterrents to wide spread adoption of CTC
while CTC also needs to be as time efficient as possible in order to effectively serve the
role of population screening for colorectal cancer, investigating the effect of simethicone
to prevent the colonic bubbles on the time efficiency of CTC interpretation would be
important. If simethicone can resolve the colonic bubble problem, CTC can be performed more
conveniently for the patients as well as for the interpreting radiologists.

This study is to determine whether colonic bubbles associated with CT colonography performed
with iohexol for fecal/fluid tagging could be reduced and the interpretation time of the CT
colonography could be shortened by adding simethicone to the standard cathartic preparation.

Inclusion Criteria:

- Adult patients who are schedule to undergo colonoscopy for a suspicion of colonic
neoplasia at the investigators' institution

- Those who agree to participate in the study

Exclusion Criteria:

- Colonoscopy for reasons other than detecting colonic neoplasia, e.g. evaluation of
inflammatory bowel disease

- Contraindications to iodinated contrast including renal insufficiency,
hypersensitivity, and hyperthyroidism

- Acute severe colonic obstruction which is likely preclude safe and successful
performance of CTC

- Patient who is suspicious for colonic perforation

- Pregnancy

- Phenylketonuria (contraindication to simethicone)

Type of Study:


Study Design:

Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Investigator, Outcomes Assessor), Primary Purpose: Diagnostic

Outcome Measure:

Interpretation time

Outcome Description:

Time to interpret the colonic findings of CT colonography

Outcome Time Frame:

within 3 months after enrollment of all the patients and acquisition of CT colonography in all enrolled patients

Safety Issue:


Principal Investigator

Seong Ho Park, MD

Investigator Role:

Principal Investigator

Investigator Affiliation:

Asan Medical Center


South Korea: Institutional Review Board

Study ID:




Start Date:

February 2013

Completion Date:

January 2014

Related Keywords:

  • Colorectal Neoplasms
  • Neoplasms
  • Colorectal Neoplasms