The routine abdominal films consist of supine and upright views. If the patient cannot stand for an erect abdominal film and a PA view of the chest, the cross-table lateral projection with the right side elevated may be used to assess pneu-moperitoneum and air-fluid levels. As little as 1 to 2 mL of free air in the peritoneal space may be identified if the films are appropriately obtained. The PA view of the chest is usu-ally obtained as part of an acute abdominal series because an abnormality in the chest may have symptoms referred to the abdomen. Oblique views of the abdomen may be obtained, if needed.
Plain abdominal radiography is less sensitive in evaluat-ing solid organs or metastases. In recent years, increased use of cross-sectional techniques, such as ultrasonography and CT, has shown them to be more sensitive in assessing disor-ders of the abdominal solid organs and metastatic diseases. Acute cholecystitis is better assessed by ultrasonography or nuclear medicine studies.