Evaluation Of Small Intestine Distention And Small Intestine Wall Appearance By Using Different Oral Contrast Agents For Multi-detector Row CT

Subject:In order to find the best oral contrast agent for MDST enterography, we used different oral contrast agents for patients who had whole abdominal MSCT exam and made comparisons of the distention and structural appearance of small intestine wall.Materials:We chose 80 patients who had taken whole abdominal multi-detector row CT, including 43 female and 37 male with average age about 52.65±15.56 years. We divided the patients into 4 groups by taking different oral contrast agents with 1800ml total volume:pure water for Group 1, milk for Group 2,1:30 lactulose diluted solution for Group 3 and 2.5% mannitol for Group 4. We asked the patients to start to drink the contrast 45 minutes prior to the exam and take the contrast 4 times with 450ml volume per 15 minutes. After the CT scanning, results were independently reviewed by two radiologists who were blind to the oral contrast agent usage. The degree of intestinal distention was quantitatively measured by the outside diameter of the best dilated intestinal lumen. Differences were evaluated by using the ANOVO test at a confidence level of 95%. The degree of distention was also qualitatively scored on a four-point scale. And the visualization of mural detail was qualitatively scored on a two-point scale. CT values, contrast Coefficient of enteric cavity and intestinal wall density and enteric cavity were measured at 45s after enhancement scanning, which were qualitatively scored on a three-point scale.Results:The mean width of small intestinal lumens in water, pure milk, diluted lactulose solution,2.5% mannitol groups were:1.44±0.49,1.86±0.32,1.98±0.35,1.99±0.27. There was a significant difference in intestinal distention between four groups with P<0.05 and the intestinal dilatation of diluted lactulose solution and 2.5% mannital groups was better. But there was no significant difference between these two groups. The mean difference of CT value between intestinal wall and lumen after enhancement in these four groups were: 83.75±5.00,78.90±17.00,82.15±5.14,82.70±5.38HU. There was no significant difference in these four groups with P>0.05. The score of small intestinal lumen distention extent,wall detail visualization and contrast extent (between lumen and wall) in wate,Pure milk, diluted lactulose solution,2.5% mannitol group was 7,0.9,45,13,24,55,15,32,56,16.34. The scores of diluted lactulose solution and 2.5% mannitol group had high score than other two groups..Conclusion:In 2.5% mannitol and diluted lactulose groups, there were18 cases (18/20) in each group in which the score of small intestinal distention was above 3 points. Both 2.5% mannitol and diluted lactulose can make almost over 80% small intestine dilated well and let the intestinal structure shown very clearly. Accordingly, 2.5% mannitol and diluted lactulose are both suitable oral contrast agents for CT enterography and lactulose which has less adverse effect in gastrointestinal tract is the first choice.