The abdominal x-ray shows
paucity of gas in the abdomen. Above x-ray finding in a neonate with bilious vomiting should raise high index of suspicion for gut malrotation and the patient should be referred to paediatric surgeon emergently.
Clinical presentation of bilious vomiting alone should be treated as due to a surgical cause irrespective of plain x-ray findings as abdominal x-ray can be normal or may show paucity of bowel gas. Upper GI series is currently considered ‘gold standard’ test to diagnose gut malrotation.
Further reading – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4176790/