Subtraction CT colonography: feasibility in an animal model
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Updated: Aug 26, 2026
Flexible Colonoscopy in Mice to Evaluate the Severity of Colitis and Colorectal Tumors Using a Validated Endoscopic Scoring System
Published on: October 16, 2013
D G Sheppard1, R B Iyer, D Herron
1Department of Radiology, The University of Texas, M.D. Anderson Cancer Center, Houston 77030, USA.
Aim:
To determine, in an in vitro animal model, the feasibility of subtracting residual faecal material, during virtual colonoscopy, by uniform mixing of the colonic contents with barium.
Materials And Methods:
Segments of animal colon containing simulated soft-tissue polyps, measuring 3-10 mm, were filled with a faecal substitute consisting of a barium and peanut butter mix that had an attenuation value greater than 200 Hounsfield units. The colonic segments were then examined by CT using 3-10 mm beam collimations, and at pitch factors of 1 and 2. Using subtraction cut-off levels varying from 100-250 Hounsfield units, the barium and peanut butter mix was then subtracted to reveal the underlying polyps.
Results:
Our optimal technical parameters required 3-mm beam collimation, a helical pitch factor of 2, reconstruction intervals of 3 mm, and a subtraction cut-off level of 150 Hounsfield units. The subtraction technique, in this animal model, had a sensitivity of 94% and a specificity of 80% for polyps measuring greater than 3 mm.
Conclusion:
In this limited animal model, the subtraction technique utilized was technically feasible and had an acceptable sensitivity.
