Thoracic Vascular Injury
Section snippets
Mediastinal hemorrhage and thoracic vascular injury
The presence of mediastinal hemorrhage is an important clue to potential major thoracic vascular injury, which most commonly involves the proximal descending thoracic aorta at the level of the left mainstem bronchus and left pulmonary artery. Chest radiography provides the initial assessment of mediastinal contour. Although several articles have described apparently reliable radiographic signs of hemomediastinum [10], [11], [12], [13] and potential aortic injury, subsequent larger series
Multirow detector CT technique
In general, MDCT is more sensitive than is chest radiograph for the diagnosis of most traumatic thoracic pathology [19], and typically it is indicated for patients who have experienced blunt polytrauma. Using bolus tracking with a threshold of 90 Hounsfield units (HU) set in the proximal ascending aorta, the author performs a 16 × 0.75–mm or 16 × 1.5–mm scan (in large patients) of the entire chest, and reconstructs data at 3- or 5-mm intervals. If needed in questionable cases, the raw data are
Penetrating aortic injury
In general, the concepts that apply to CT imaging in blunt aortic trauma are not valid regarding penetrating injury. The major role of CT (as described elsewhere in this issue) is determination of the presence or absence of mediastinal involvement along or near the course of the penetrating object. In some cases, however, in the pursuit of this goal, direct findings of injury to major mediastinal structures can be diagnosed. Aortic or major arterial injuries can be detected, and appear as
Thoracic aortic branches
Injuries of the primary branches of the aorta are uncommon relative to the proximal descending aorta, but represent a significant potential isolated injury or one that is concurrent with aortic injury [Fig. 11, Fig. 26] [35]. Chen and colleagues [36] studied 85 patients who had either aortic, isolated branch vessel, or both concurrently in 71 (83.5%), 11 (13%), and 3 (3.5%) patients, respectively. Ahrar and colleagues [37] identified 81 patients who had angiographic evidence of traumatic injury
Major venous thoracic injuries
Based on a literature review, injuries to the major thoracic veins from blunt trauma seem to be extremely rare. Most likely, these injuries often are fatal, and therefore, rarely are imaged.
Intrapericardial inferior vena cava injury should be considered in cases of major hepatic injury, particularly if there is blood around the intrahepatic inferior vena cava or extravasation of contrast material. Superior and inferior vena cava injury also should be considered in cases of pericardial tamponade
Summary
The availability of MDCT has increased the use of CT and its accuracy as a screening study for traumatic aortic injuries. In general, CT has become much more commonly used in screening for major injuries in patients who have experienced blunt polytrauma. Therefore, an understanding of the CT signs of TAI and pitfalls in the diagnosis need to be well recognized by all radiologists and other physicians who view this study. Angiography (see elsewhere in this issue) and transesophageal sonography
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