Normal colonic wall thickness at CT and its relation to colonic distension

Purpose: The purpose of this work was to analyze the relation between normal colonic wall thickness at CT and local colonic distension. Method: One hundred consecutively acquired patients were included in our study. All patients were asymptomatic regarding their intestine, and their history was always negative for intestinal disease. All CT examinations were performed for other reasons than intestinal disease. Colonic wall thickness at CT was measured digitally in every patient at four locations and set in relation to the local colonic distension. Results: The normal colonic wall thickness ranged from 0 to 2 mm in colonic segments with a diameter of greater than or equal to4-6 cm, from 0.2 to 2.5 mm in colonic segments with a diameter of 3-4 cm, from 0.3 to 4 mm in colonic segments with a diameter of 2-3 cm, and from 0.5 to 5 mm in colonic segments with a diameter of 1-2 cm. Maximal colonic wall thickness ranged up to 6 and 8 mm in the proximal and distal colon, respectively, if the measured colonic segment showed a luminal width of <1 cm according, to contraction. Discussion: The normal colonic wall thickness at CT should be regarded as a dynamic value that stays in clear relation to the local colonic distension. In contracted colonic segments, a colonic wall thickness of 6-8 mm may still be normal. On the other hand, a colonic wall measuring 5 and 3 mm should be regarded as thickened if found in colonic segments with a luminal width of >2 and 4 cm, respectively.