Selective Use of Ultrasonography for the Detection of Pneumoperitoneum

Abstract

OBJECTIVE: Whether ultrasonography is superior to plain radiography for the detection of pneumoperitoneum is unknown. The goal of this study was to determine the value of ultrasonography for the detection of pneumoperitoneum. METHODS: One hundred thirty-two patients with suspected hollow-organ perforation were prospectively selected for study. All 132 patients received ultrasonography, upright chest radiography, and left lateral decubitus abdominal radiography examinations. The diagnostic accuracies of chest and abdominal radiographs for the detection of pneumoperitoneum were compared with corresponding values from ultrasonography. RESULTS: Of the 125 patients who underwent laparotomy, 121 patients had hollow-organ perforation, three patients had perforated appendicitis, and one patient had acute cholecystitis. For the diagnosis of pneumoperitoneum, ultrasonography demonstrated a sensitivity of 93%, a specificity of 64%, a positive predictive value of 97%, a negative predictive value of 44%, and an accuracy of 90%. Plain radiography revealed a sensitivity of 79%, a specificity of 64%, a positive predictive value of 96%, a negative predictive value of 21%, and an accuracy of 77%. CONCLUSIONS: Ultrasonography is a more sensitive diagnosing modality than plain radiography for the diagnosis of pneumoperitoneum. The authors suggest that ultrasonography was a useful diagnostic modality when plain radiographs failed to reveal pneumoperitoneum among patients with suspected hollow-organ perforation.