· The clinical difference between bilious and non-bilious vomiting is critical because it distinguishes between life threatening surgical abnormalities such as malrotation and midgut volvulus and less urgent entities like duodenal atresia and pyloric stenosis. If true non-bilious vomiting is present the first examination is a plain film of the abdomen and pelvis to evaluate the bowel gas pattern and other structures. If the infant is <6-7 weeks of age this is followed by an US of the right upper quadrant to evaluate potential pyloric stenosis. If the infant is >6-7 weeks of age the next examination is typically an upper gastrointestinal fluoroscopy (UGI). Further imaging, if necessary, should be performed after consultation with the pediatric radiologist.