Hepatic trauma: CT findings and considerations based on our experience in emergency diagnostic imaging.

Abdominal blunt trauma represents the main cause of death in people of age less than 40 years; the liver injury occurs frequently, with an incidence varying from 3 to 10%. Isolated hepatic lesions are rare and in 77-90% of cases, lesions of other organs and viscera are involved. Right hepatic lobe is a frequent site of injury, because it is the more voluminous portion of liver parenchyma; posterior superior hepatic segments are proximal to fixed anatomical structures such as ribs and spine that may have an important role in determining of the lesion. The coronal ligaments' insertion in this parenchymal region augments the effect of acceleration-deceleration mechanism. Associated lesions usually are homolateral costal fractures, laceration or contusion of the inferior right pulmonary lobe, haemothorax, pneumothorax, renal and/or adrenal lesions. Traumatic lesions of left hepatic lobe are rare and usually associated with direct impact on the superior abdomen, such as in car-crash when the wheel causes a compressive effect on thorax and abdomen. Associated lesions to left hepatic lobe injuries correlated to this mechanism are: sternal fractures, pancreatic, myocardial, gastrointestinal tract injuries. Lesions of the caudal lobe are extremely rare, usually not isolated and noted with other large parenchymal lesions. The Institution of Specialized Trauma Centers and the technical progress in imaging methodology developed in the last years a great reduction of mortality. New diagnostic methodologies allow a reduction of negatives laparotomies and allow the possibility of conservative treatment of numerous traumatic lesions; however, therapy depends from imaging findings and clinical conditions of the patient. Computed tomography (CT) certainly presents a large impact on diagnosis and management of patients with lesions from blunt abdominal traumas. It is important to establish a prognostic criteria allowing decisions for conservative or surgical treatment; CT findings and peritoneal fluid evaluation may be used to make a first differentiation of severity of lesions, but haemodynamic parameters may help the clinician to prefer a conservative treatment. In emergency based hospitals and also in our experience, positive benefits spring from diagnostic accuracy and consequent correct therapeutic management.