Multidetector Computed Tomography of Nonosseous Thoracic Trauma

Abstract

the patient's immediate course (as in the setting of acute aortic injury or blunt cardiac injury). Even when not life threatening, the presence of thoracic injury may affect management. A pneumothorax, for example, may require emergent thoracostomy tube placement before surgical correction of a pelvic fracture. Chest radiography remains a frequently used screening tool owing to its low cost and portability. Multidetector computed tomography (MDCT) continues to make inroads in the evaluation of radiographic abnormalities and in the exclusion of significant injury in the setting of an appropriate mechanism (high-speed collision or high fall) in the posttrauma patient. The increase in the use of computed tomography (CT) has been driven by its ready availability at all hours, its ability to detect subtle disease missed by radiography, and its ability to change management in almost one-fifth of trauma patients. 2,3 Most often, CT is performed to evaluate abnormal findings on chest radiograph,butoccasionally MDCT maybeusedas a firstline tool. The goal of this article is to highlight the features of blunt and penetrating thoracic traumatic conditions, including aortic and cardiac injury, on MDCT images. Occasionally, these conditions may be encountered in isolation, but more often, they are seen in conjunction with other injuries (both intrathoracic and extrathoracic). Technique Unlesscontraindicated basedonallergy orrenalfailure,MDCT in the setting of trauma should be performed with the use of intravenous contrast. The potential benefit of visualizing direct signs of vascular injury or an area of blush (indicative of active extravasation or pseudoaneurysm formation) far outweighs anytheoreticalrisks.MDCTofthethoraxshouldbeperformed using a technique that allows high-quality multiplanar reconstructions (MPRs) and provides source images that allow volume-rendered images as well. At our institution, we scan using a pitch of 1 with 3-mm reconstructions at 2-mm intervals. The 33% overlap allows for high-quality MPRs and yet, 3-mm images do not result in an inordinate number of images. The balance between a manageable image burden and thin sections has become harder in the MDCT era. We only scan once in the setting of trauma. We have not found precontrast images of any help.