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?
Acute mesenteric ischemia Emphysematous cholecystitis Gallstone ileus Obstructed right inguinal hernia