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Multidetector-Row CT Colonography: Optimisation of Reduced Bowel Preparation Regimes and Diagnostic Performance in Comparison to Colonoscopy

Phase 4
50 Years
Not Enrolling
Patients With Potential Colorectal Neoplasia

Thank you

Trial Information

Multidetector-Row CT Colonography: Optimisation of Reduced Bowel Preparation Regimes and Diagnostic Performance in Comparison to Colonoscopy

CT colonography has been shown to be accurate in detection of colorectal neoplasia in
enriched patient populations and is generally preferred by patients to conventional
endoscopy and barium enema. It is advocated as an acceptable alternative for colorectal
cancer screening and is increasingly used in the investigation of symptomatic patients.
Ideally, like conventional colonoscopy, CT colonography requires a clean colon, free of
residual stool and fluid. There is however good evidence that the arduous bowel purgation
regimes required may produce adverse effects such as electrolyte imbalance, and are more
detrimental to overall patient experience and compliance than any subsequent investigation.
An ability to perform CT colonography with reduced bowel purgation, whilst maintaining
acceptable diagnostic accuracy, would undoubtedly make the technique a more attractive
proposition both for population screening and investigation of symptomatic patients.

Interest has been generated in the use of orally ingested dilute barium or ionated contrast
medium prior ro CT colonography to "label" or "tag" residual fluid or faecal matter reduced
laxative. Such oral contrast agents are highly attenuating to X-rays such that labeled
residual bowel contents appear white on CT scanning and are readily distinguished from true
colonic pathology.

Despite the early promise of a few limited studies, there is no consensus as to the optimum
oral contrast type, dose and concentration. Anecdotally barium tends to best label solid
residue whereas iodinated contrast best labels fluid, but this assumption has not been
proven. Furthermore it is known that iodinated contrast tends to draw fluid into the bowel,
producing a wet colon, which may not be suited to CT colonography. However, this indrawing
of fluid by iodinated contrast such as gastrograffin produces a mild laxative effect, which
may obviate the need for further formal purgation.

The study aims to establish the optimum reduced preparation-tagging regimen, establish
patient experience and document diagnostic performance compared to conventional colonoscopy.

Inclusion Criteria:

- Patients who are under investigation for suspected colonic neoplasia and over 50
years old:

1. Symptomatic patients eg. change in bowel habit, rectal bleeding etc.

2. Polyp surveillance

3. Strong family history

4. suspected neoplasia on previous investigation (e.g. barium enema)

Exclusion Criteria:

- patients under 50 patients undergoing surveillance for inflammatory bowel disease
(due to poor diagnostic use of CT colonography in this specific patient cohort)

Type of Study:


Study Design:

Allocation: Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Parallel Assignment, Masking: Open Label, Primary Purpose: Diagnostic

Outcome Measure:

Which of four combinations of low residue diet, reduced laxative dose and oral contrast agent is best tolerated by patients and optimally prepares the colon prior ro CT colonography

Principal Investigator

Stuart Taylor, MD

Investigator Role:

Principal Investigator

Investigator Affiliation:

St Mark's Hospital, North West London NHS Trust; & University College Hospital


United Kingdom: National Health Service

Study ID:




Start Date:

July 2004

Completion Date:

February 2006

Related Keywords:

  • Patients With Potential Colorectal Neoplasia
  • colorectal neoplasia
  • CT colonography
  • faecal tagging
  • Neoplasms