Abstract: Objective A new type of low density gastrointestinal tract contrast agent is prepared by using simple and easily available materials, so as to realize accurate display and positioning of gastrointestinal bleeding. Methods Using edible whipped cream and xanthan gum as materials, a low density contrast agent was prepared after stirring with a mixer at 160-260 r/min for about 5 minutes at a temperature of about 7 ℃. Then test its stability at different temperatures, observe its uniformity on the CT scan image and measure the CT value, compare its density with the blood clot, and finally use the pig's small intestine, saline bag and plasma mixed with heparin to simulate gastrointestinal bleeding, to compare its display and positioning effect on hemorrhage foci with water, so as to explore the application value of this low-density contrast agent in gastrointestinal hemorrhage. Results The low density contrast agent showed good stability at room temperature （25 ℃） and refrigerator temperature （2 ℃~4 ℃）; the CT scan image showed that its uniformity was relatively high, and the measured CT value ranges -500 to -700 Hu, which is obviously different from the density of blood clot; compared with water, this low density contrast agent has obvious advantages in the display and positioning of hemorrhage foci. Conclusion The gastrointestinal lowdensity contrast agent made of edible whipped cream and xanthan gum has good stability and high uniformity, it can display and locate the hemorrhage foci accurately, so it has an important clinical value for the diagnosis of gastrointestinal bleeding.

Key words: contrast agents, gastrointestinal bleeding, computed tomography

摘要： 目的 利用简单易得的原料制备一种新型的胃肠道低密度造影剂,从而实现对消化道出血的准确显示及定位。方法 以可食用淡奶油和黄原胶为原料,在约7℃的温度条件下,经搅拌机以160~260转/分搅拌约5分钟后制得低密度造影剂。然后在不同温度下测试其稳定性、在CT扫描图像上观察其均匀性并测量CT值、比较其与血凝块的密度差异,最终利用猪小肠、盐水袋和混入肝素的血浆模拟消化道出血,比较其与水对出血灶的显示及定位效果,从而探究该低密度造影剂在消化道出血中的应用价值。结果 该低密度造影剂在室温（25℃）、冰箱冷藏室温度（2℃~4℃）下均表现出良好的稳定性;由CT扫描图像观察到其均匀性较高,测得CT值范围为-500~-700 Hu,与血凝块的密度差异明显;与水相比,该低密度造影剂对出血灶的显示、定位有明显的优势。结论 以可食用淡奶油和黄原胶制得的胃肠道低密度造影剂具有良好的稳定性和较高的均匀性,可以准确显示并定位出血灶,对于消化道出血的诊断具有重要的临床价值。

关键词: 造影剂, 消化道出血, CT