[Intestinal contrasting in abdominal computed tomography].

In 56 patients undergoing abdominal CT the gastrointestinal tract was defined by negative contrast instead of the conventional positive contrast from an iodine containing contrast medium. The contrast material was a 2 1/2% mannitol solution and was used for filling the rectum. Filling of the gastrointestinal tract was of similar quality to that obtained with positive contrast media. The number of artifacts due to high contrast boundaries was slightly greater with the negative contrast than it would have been with positive contrast. Differentiation of the gastrointestinal tract from other abdominal organs was equally good for both methods. The negative contrast method was poor in diagnosing cystic tumours but proved much better than positive contrast for evaluating the wall of the gastrointestinal tract.