Sensitive most investigation to detect minimal intraperitoneal free air: (A) Standing x-ray abdomen, (B) Right lateral decubitus x-ray, (C) Chest x-ray, (D) Left lateral decubitus x-ray
Answer is C. Although as little as 1 ml of free gas can be demonstrated radiographically, either in chest PA or a left lateral decubitus abdominal film, CT is superior to plain radiographs in detecting minute quantities of pneumoperitoneum. Chest PA view is more sensitive than even a left lateral decubitus abdominal film.