Sonographic diagnosis of pneumoperitoneum in twelve patients

Abstract

Ultrasonography is widely accepted as the initial screening modality for patients admitted for acute abdominal pain or trauma. However, only few reports deal with the impact of sonography in the assessment of pneumoperitoneum. We report a sery of 12 patients admitted with an acute abdomen between 1990 and 1991, in whom pneumoperitoneum was first detected by sonography. Of these 12 patients, free peritoneal gas was not detected by plain film X-ray if no additional positioning technique, according to Miller [1], was used. Eleven of them were subsequently surgically proven to have a perforated hollow viscus. In one subject, the pneumoperitoneum turned out to have and external gynaecological origin.

Ultrasonography displayed the pneumoperitoneum as a hyperechogenic line located between the posterior aspect of the anterior abdominal wall and the surface of the liver. The hyperechogenic line induced strong reverberation echoes, moved synchronously along the liver surface when the patient turned from supine to left lateral decubitus and disappeared on increasing the pressure transmitted by the probe on the abdominal wall.

Knowledge of the sonographic pattern of pneumoperitoneum are important for any radiologist involved in an emergency care unit, and referring physicians should be aware of the accuracy of ultrasonography in the diagnosis of pneumoperitoneum.