Trial Information

CT Colonography Ph. I CDI Trial: Evaluation of Stool Tagging for Improved Patient Compliance

CT Colonography, a rapidly evolving technique, offers a noninvasive and efficient colorectal
screening examination, with the potential to improve patient compliance. However, currently
it requires the bowel preparation, one of the largest barriers to colonoscopy screening. A
promising new tool in CT Colonography is stool tagging, which has the potential to decrease
the amount of catharsis required by patients during the bowel preparation, while decreasing
the number of false positives due to the reader mistaking residual stool for polyps.

Our primary hypothesis is that image quality and patient compliance differ depending upon
the tagging agent and dosing schedule. Our strategy is to vary key components of recently
reported barium and iodine protocols to further optimize them and to compare our results
with existing and currently aggregating data in collaboration with other investigators.

The following aims will implement this strategy:

AIM 1: Perform a randomized control trial of specific stool tagging protocols at CT
Colonography in a well characterized cohort of patients undergoing colorectal evaluation.

Task 1A - Recruit a prospective cohort of 60 subjects, randomize them equally to three
different stool tagging protocols, and sequentially perform CT Colonography and optical
colonoscopy on them.

Task 1B - Assess image quality of CT Colonography and optical colonoscopy data by the method
of bowel preparation in the first five subjects of each arm and implement specific changes,
if necessary.

AIM 2: Analyze the CT Colonography and optical colonoscopy data to assess differences
across study arms for the outcome measures of patient preference, image quality of tagged
stool, and diagnostic reader performance.

Task 2A: Assess patient expectations regarding the bowel preparations, CT Colonography and
colonoscopy before the procedures and their preferences after the procedures.

Task 2B: Evaluate image quality, in the presence of tagged stool and fluid, of both the CT
data and the colonoscopy data.

Task 2C: Perform a multi-observer reader evaluation of diagnostic performance of CT
Colonography and colonoscopy, compared to the enhanced reference standard of colonoscopy
aided by segmental unblinding of CT results, to assess sensitivity and specificity of
colorectal polyp detection.

Upon completion, the three specific variations in stool tagging techniques will be compared
on homogenous density of tagging and patient acceptability to determine which protocol
optimizes the trade-off. Diagnostic performance of CT and colonoscopy will be compared to
the enhanced reference standard of colonoscopy aided by the segmental unblinding of CT
results. Most significantly, these results may help determine an optimal tagging protocol
to use for larger trials of CT Colonography implementation in community settings.