Imaging of traumatic lesions of abdominal viscera

Abstract

Trauma to the abdomen accounts for approximately 10% of trauma deaths. The injury may be blunt or penetrating. Abdominal organs are frequently injured from blunt trauma. Rapid acceleration-deceleration of abdominal viscera at the moment of impact generates shearing forces that result in transection or laceration of the underlying parenchyma and vessels, most commonly at points of attachment or relative fixation. Prompt recognition and management of intra-abdominal organ injury is essential in order to minimize morbidity and mortality. New imaging modalities have altered the diagnostic approach to these patients. The use of computed tomography (CT) and ultrasound has largely replaced diagnostic peritoneal lavage (DPL) in the initial evaluation of abdominal injury in hemodynamically stable patients. Ultrasound is an important method in the rapid evaluation of abdominal trauma as it is non-invasive, safe, cost-effective, readily available, portable, can be repeated as often as required and involves no radiation or use of contrast material. Its use is established in the detection of intraperitoneal fluid, but it has low sensitivity (83%) in the detection of injuries to abdominal viscera and the evaluation of the retroperitoneum. In addition, its use is further limited by the body habitus, the presence of excessive bowel gas, the existence of open wounds or subcutaneous emphysema, and by reduced ability of the patient to cooperate. Computed tomography has become the method of choice in the diagnosis of blunt abdominal trauma. It has been shown to be highly sensitive, specific and accurate in detecting the presence and the extent of injury to the abdomen. CT also provides important additional information regarding associated extra-abdominal injuries (e.g., pneumothorax, fractures). In addition, it provides useful information in patients in whom clinical abdominal examination is either equivocal or unreliable, due often to altered mental status. The overall trend towards nonoperative management of abdominal trauma is due to part in the ability of helical CT not only to define injury but to exclude significant injury, thereby making possible the avoidance of unnecessary surgery. Nowadays, magnetic resonance imaging is not used in acute abdominal trauma because of the lengthy imaging times, monitoring difficulties, the artefacts created by the metallic instruments these patients usually carry, and the lack of availability of the equipment in many centers.