Detection of pneumoperitoneum on chest radiographs: comparison of upright lateral and posteroanterior projections.

Abstract

The upright lateral chest radiograph is more sensitive than the upright posteroanterior chest radiograph in detecting small amounts of pneumoperitoneum. When there is a strong clinical suspicion of a perforated hollow viscus, it may be of benefit to include an erect lateral chest radiograph as part of the acute abdominal series.