PA Anatomy: Imaging Overview- CT

GI contrast material can be given orally or through the rectum for CT scanning, but is not always needed. It depends on what type of abnormality is clinically suspected. Timing is important for GI contrast, particularly when given by mouth. If it is all given at once, then it does not spread out through the entire GI tract. To get contrast throughout the GI tract requires several hours of oral sipping of the contrast material, which is sometimes not practical. For CT, either barium or Iodine-based contrast can be used in the GI tract. Both will look the same on the images.

These are axial images of two different patients. Image A has oral contrast in their stomach (labeled with S).Image B does not. Depending on how much the contrast is diluted by other fluids, it may appear as white as bone, or less white, as in image A.

This patient received oral contrast, but after sipping for a while, threw up the last dose that was given. Their stomach (S) does not look very white, but there are several adjacent small bowel loops (B) that did get filled with contrast.

This patient received rectal contrast. The rectum (R) has very dense (white) contrast material in it, as dense as bone. It is hard to get contrast all the way to the rectum without diluting it when using the oral route.