An 85-year-old woman hasa 48-hour history of generalized abdominal pain and vomiting. On examination, she is dehydrated multiple dilated small bowel loops measuring up to 4 cm in diameter. A linear gas-filled structure is present in the right upper quadrant with short branches extending from it. What is the most likely diagnosis?

Ans CSmall bowel obstruction in an elderly patient with evidence of pneumobilia is suggestive of Gall stone ileusQ. Imaging features of gall stone ileus are: Pneumobilia which appears as central branching air lucencies in the liver, small bowel obstruction and radiopaque density in the abdomen (most common site of impaction is the terminal ileum).