Sonographic detection of blunt hepatic trauma: hemoperitoneum and parenchymal patterns of injury.

OBJECTIVES: To determine the sensitivity and utility of emergency sonography for the detection of blunt hepatic injury (BHI) in patients with abdominal trauma and to describe parenchymal sonographic patterns of BHI.
METHODS: This report was a prospective clinical study in which the findings of all patients who had emergency sonograms were recorded on a data sheet by the initial sonographer and interpreting physicians. All patients with hepatic injuries during this period were identified and physical examination, laboratory, computed tomographic and intraoperative findings were compared with the prospective data sheets.
RESULTS: From January of 1995 to December of 1998, 2,622 emergency sonograms were performed, and in this group, a total of 146 patients had BHI. Emergency sonograms allowed detection of free fluid in 98 patients (67%), and parenchymal injury with no free fluid in seven patients (5%). There were 41 false negatives (28%). The most common pattern identified on a sonogram was a discrete area of increased echogenicity followed by a diffuse hyperechoic pattern. Seventy-six patients (52%) had concomitant intra-abdominal injuries, including spleen (n = 46), bowel (n = 30), and kidney (n = 19). There were 102 exploratory laparotomies performed. Abdominal tenderness or distention was present in 127 patients (87%), and 108 patients had right rib fractures (74%). Based on detection of free fluid, parenchymal injury, or both, the overall sensitivity of sonography for the detection of BHI was 72 % but was 98 % for grade III or higher injuries.
CONCLUSION: Emergency sonography is sensitive for the detection of grade III or higher liver injuries resulting from blunt abdominal trauma. Sonography may also reveal BHI on the basis of parenchymal abnormality, with a discrete hyperechoic area the most commonly encountered pattern.