Per-oral negative contrast agent for abdominal CT

A method of CT imaging the gastrointestinal tract, including at least the upper part of the small intestine, of a subject, the method comprising:

• a) prior to the CT imaging, orally administering to the subject to be examined an edible negative contrast agent for CT imaging of the gastrointestinal tract intended for oral intake, the contrast agent being a fluid, aqueous foam displaying a CT density contrast value in the range −300 to −800 HU, wherein the contrast agent comprises an aqueous continuous liquid phase having a pH of 6.5 to 8.0, the aqueous continuous liquid phase comprising:
• 0.1 to 5 wt % of a surfactant, the surfactant being a protein;
• 0.01 to 1.0 wt % of a hydrocolloid acting as foam stabilizer;
• a buffering agent;
• and
• water;
• and gas bubbles dispersed in the continuous aqueous liquid phase, the contrast agent having a consistency of 7 to 12 cm as measured with Bostwick consistometer over 30 seconds at 23±1° C., wherein the weight ratio surfactant hydrocolloid in the continuous liquid phase is from 8:1 to 2:1;
• and
• b) using a computerized tomography to obtain a CT image of the subject's abdomen.