Figure 4.

Representative iodine density map images of small bowel in rabbits enhanced with double-contrast (enteric bismuth or tungsten or tantalum contrast, and intravenous iodine contrast). Small bowel wall (arrowheads) visualization score was significantly better in an intravenous contrast-only conventional CT image (A) than in an iodine density map from enteric bismuth-enhanced double-contrast DECT (B) where the curvilinear bowel wall was indistinct and bowel lumen contrast poorly subtracted. Note that air appears bright on the iodine/bismuth material decomposition (B) due to a software-associated artifact, further detailed in the methods section. Images (C) and (D) are iodine density maps of double-contrast DECT where enteric tungsten and tantalum contrast were used respectively. These latter images show near complete subtraction of the intraluminal tungsten and tantalum contrast, respectively, and vividly show the curvilinear bowel wall enhancement by the intravenous iodinated contrast material. The small bowel wall visualization for the iodine density map of tungsten and tantalum enteric contrast enhanced DECT was comparable with but not significantly preferred over that of intravenous-contrast-only conventional CT (A).