Utilization of Milk as an Oral Contrast Agent in CT Scan of the Abdomen

Negative oral contrast agents used for evaluation of lesions of the gut which could be better elineated due to gut distension. Volumen with 0.1% barium sulphate suspension is being recommended as low-density contrast agent. However, there are some drawbacks such as cost, limited availability, and some patient discomfort such as nausea and vomiting as well as poor palatability. 

Low-attenuation oral contrast agent using water for helical CT of the abdomen was used by Winter

which exquisite luminal and upper gastrointestinal tract mucosal depiction. However, using of water requires the adding of a smooth muscle relaxant of the upper gastrointestinal and does not give adequate evaluation of the distal small bowel.

We expected that used milk of 4% fat as contrast agent used orally could produce results comparable to those obtained with corn oil emulsion but without the unfit high content of fat. Furthermore, the milk fat could be sufficient to decrease peristalsis of gastrointestinal tract. This could allow upper gastrointestinal tract distention and mural discrimination that were superior to those obtained by water. 

Although promising results have been achieved, but the study sample was limited to those patients undergoing CT Scan of Abdomen and Pelvis with the use of water as oral contrast. Additionally, the degree of distention evaluated by both radiologists was subjective depending on naked eye. The timing of drinking milk was not properly adjusted to allow for filling the large bowel due to pre scheduled appointments.

Hence, the replacement with whole milk with 4% as in the present study, fat content has been shown to be as effective in distension of the gut and also takes care of the disadvantages of Volumen. It is also a preferred agent in pediatric cases. A larger study needs to further corroborate these observations. Gastric distension and visualization as well as duodenum, jejunum, and proximal bowel was significantly improved with milk as a low-attenuation contrast agent.

Gastric distention of milk was appreciated where the present study demonstrated excellent distension and visualization of the stomach and was good and fair for duodenum, jejunum was significantly improved with milk as a contrast agent. It showed an attractive oral contrast agent, giving good gastrointestinal distension and landmark discrimination. These results are in agreement with that Mitka 2007 and Meyer and Gawde 2012 while A pisarnthanarak et al. (2013) stated that apart from collapse of the gallbladder, increase of GI adverse symptoms was another major drawback of whole milk when used as CT oral contrast, especially in Thai people.

Results of Thompson demonstrated that whole milk were superior to other agents used for gastrointestinal distention, mural visualization, and pancreas-duodenum discrimination. In bowel loop discrimination, results with 3.8% milk were synonymous to those with barium but superior to water for bowel distension and significantly superior to 0.1% gastrografin. However, 10% of patients who received 3.8% milk reported immediate post-test diarrhoea. No side effects were documented for patients who received water and 0.1% gastrografin. 3.8%

milk is an effective and superior neutral oral contrast agent for the assessment of the jejunum, ileum and terminal ileum in CT enterography. However, further studies are needed to explore other suitable oral contrast agents for CT enterography in lactose- or cow’s milk-intolerant patients .

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