Sonographic diagnosis of bowel obstruction presenting with fluid-filled loops of bowel

When intestinal obstruction presents with fluid‐filled bowel loops instead of air‐distended loops, subtle elongated masses representing these bowel loops may be missed on plain abdominal radiographs. In these cases, ultrasound will show sausageshaped, cystic structures, with uneven margins representing mucosal folds, distributed throughout the abdomen and sometimes accompanied by peristalsis. These features differentiate fluid‐filled bowel loops from other cystic structures in the abdomen and help make a diagnosis of bowel obstruction.