Before the procedures patients drank barium sulfate suspension (15 cases) or ferrous gluconate syrup (15 cases), and other 15 cases did not drink contrast media (used as control).

• 检查前，15例口服硫酸钡溶液，15例口服葡萄糖酸亚铁糖浆溶液，15例未口服造影剂作为对照。