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

AJR Am J Roentgenol. 1995 Jul;165(1):45-7. doi: 10.2214/ajr.165.1.7785629.

Abstract

Objective: This study was done to determine whether upright lateral chest radiographs were more sensitive than upright posteroanterior chest radiographs in detecting pneumoperitoneum.

Subjects and methods: We prospectively evaluated the ability of upright posteroanterior and lateral chest radiographs to show subdiaphragmatic air in 100 consecutive patients with known pneumoperitoneum from a variety of causes. The difference in sensitivity between the two was evaluated by means of McNemar's test.

Results: The upright lateral chest radiograph showed pneumoperitoneum in 98% of the cases; the upright posteroanterior chest radiograph showed pneumoperitoneum in only 80%. The upright lateral chest radiograph was significantly better at showing pneumoperitoneum than was the upright posteroanterior chest radiograph (p < .01).

Conclusion: 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.

Publication types

  • Clinical Trial
  • Comparative Study
  • Controlled Clinical Trial

MeSH terms

  • Humans
  • Pneumoperitoneum / diagnostic imaging*
  • Posture
  • Prospective Studies
  • Radiography, Thoracic / methods*
  • Sensitivity and Specificity