CT of false-negative peritoneal lavage following blunt abdominal trauma.

The CT findings are presented in a patient with blunt trauma and a false-negative peritoneal lavage due to extraperitoneal insertion of the lavage catheter. Computed tomography correctly identified the presence of hemoperitoneum and the site of injury involving the small bowel mesentery. The diagnostic accuracy in peritoneal lavage and its relationship to abdominal CT is reviewed.