Computed tomography of the large bowel wall. Choice of slice thickness and intraluminal contrast medium.
OBJECTIVE
To determine the relative contribution of slice thickness and intraluminal contrast density to imaging of the large bowel wall.


METHODS
The authors used phantom experiments to evaluate the partial volume averaging of 2-, 4-, and 8-mm slices on imaging a single density interface (320/-100 HU) and 5 dual-density interfaces (320/50/-100 HU, 160/50/-100 HU, 0/50/-100 HU, -100/50/100 HU, and -1000/50/100 HU). For the experiments with a dual-density interface, which simulated the bowel wall, the phantom was scanned at an angle 45 degrees to the scan plane.


RESULTS
The most accurate display of interfaces was obtained with a slice thickness of 2 mm. When using 8-mm slices, walls can appear to be much thinner or thicker than normal or not even recognizable as a wall depending on the densities in the interface. Adjusting the density of the intraluminal contrast medium to within the range of the mean and window setting will improve the representation of the bowel wall.


CONCLUSIONS
Slice thickness has a significant influence on the true representation of the bowel wall using computed tomography. This effect is greater than the effect of the intraluminal contrast medium density.
Scholten
E T
ET
Department of Diagnostic Radiology, Kennemer Gasthuis, Haarlem, The Netherlands.
Ziedses des Plantes
B G
BG
Falke
T H
TH
D003287:Contrast Media; D006801:Humans; D007420:Intestine, Large / Q000000981:diagnostic imaging*; D019047:Phantoms, Imaging; D014057:Tomography, X-Ray Computed
D003287:Contrast Media