Figure 6-12 Pneumothorax.

A, Schematic of normal lung. B, Schematic of pneumothorax. Pneumothoraces can range in size from tiny to massive—we examine some tension pneumothoraces in later figures. Because of the variability in their size and location, pneumothoraces can be difficult to detect on chest x-ray. For example, a pneumothorax that is anterior or posterior rather than lateral may be hidden on frontal chest x-ray, particularly one taken in the supine position. An upright chest x-ray should be obtained if possible. An expiratory film is thought to be more sensitive, because the lung and thorax decrease in size during expiration, but air trapped in the pleural space remains the same size and thus appears relatively larger. Subtle pneumothoraces may not be visible on chest x-ray. In some cases, subcutaneous air may be the only visible clue to underlying lung injury. CT is extremely sensitive for pneumothorax, although controversy remains over the proper management of pneumothoraces seen only on CT (see text). Ultrasound is also thought to be more sensitive than chest x-ray for detection of pneumothorax, although again, the management of pneumothorax seen only on ultrasound is uncertain, because this is a relatively newly described method of detection. The chest x-ray findings of pneumothorax include a lack of the normal lung markings, which should be visible to the periphery of the chest wall. Sometimes a line marking the boundary of the lung and visceral pleura is visible, although this can be confused with ribs and with the medial margin of the scapula. Depending on the degree of pneumothorax and lung collapse, the lung parenchyma may appear denser than the opposite side. In extreme cases of tension pneumothorax, the pressure exerted by the air in the pleural space may begin to displace other structures, including the diaphragm and mediastinum. In tension pneumothorax, the hyperinflated hemithorax may also have abnormally positioned ribs, with a position more horizontal than usual. Review the figures that follow for examples of varying degrees of pneumothorax. Subtle cases can be hard to reproduce in print.

Figure 6-13 Pneumothorax.

A, PA x-ray demonstrating a very large spontaneous pneumothorax. B, Close-up from A. This image demonstrates the classic features described in Figure 6-12 no lung markings to the periphery of the thorax, a visible visceral pleural line, and increased density of the lung parenchyma—resulting from the marked degree of collapse in this case. Is this a tension pneumothorax? Some would argue that the definition of tension pneumothorax is clinical, based on hypotension and exam findings such as jugular venous distension and tracheal deviation. On a radiographic basis, tension pneumothorax is marked by some combination of tracheal deviation, mediastinal deviation to the opposite side, depression of the diaphragm and a deep sulcus (costophrenic angle), and elevation of ribs to a more horizontal position. This patient may have slight tracheal deviation and a degree of mediastinal shift, but the diaphragm appears normal, there is no deep sulcus sign, and the ribs are oriented normally. The white dots seen on each side are nipple markers.

Figure 6-14 Pneumothorax.

Same patient as Figure 6-13. The lateral chest x-ray is not usually diagnostic, even in dramatic cases such as this one, because the normal thorax is superimposed upon the abnormal. Here, a hint of the complete collapse of the left lung is seen, with increased density near the hilum, but the lateral x-ray is neither necessary nor particularly helpful in this case.

Figure 6-15 Pneumothorax.

The same patient as Figures 6-13 and 6-14 after placement of a thoracostomy tube and reexpansion of the left lung. A, AP chest x-ray. The mediastinum appears wider than in Figure 6-13 because of the AP technique in this x-ray. B, Close-up from A. Although the chest tube placement appears a bit suboptimal, it clearly is functioning, because there is complete resolution of the abnormalities noted on the original x-ray. The thoracostomy tube shows typical features including a radiopaque line, punctuated by breaks marking the location of its fenestrations (B).

Figure 6-16 Pneumothorax.

A, Supine portable chest x-ray. B, Close-up from A. This moderate pneumothorax is much subtler than in Figure 6-13 but demonstrates many of the same findings. A pleural line is faintly visible—beyond this line, no lung markings are visible. Compare this with the opposite side, where the fine markings of pulmonary blood vessels are seen to the periphery of the pleural space. Although the normal result of a pneumothorax is a more lucent hemithorax, the entire right thorax appears somewhat denser in this case; the CT from the same patient in Figure 6-18 illustrates why. It is a good practice to find and follow the scapular border and rib borders to avoid confusion of these lines with the pleural line of a pneumothorax. None of the findings of a tension pneumothorax are present in this chest x-ray. The right costophrenic angle and lateral diaphragm are somewhat indistinct. This, plus the density of the right hemithorax, should make you consider hemothorax or pulmonary contusion, in addition to the pneumothorax.

Figure 6-17 Pneumothorax.

Same patient as Figure 6-16. A chest tube has been placed, and the previously seen pleural line and absence of lung markings have resolved. The right chest looks somewhat less dense than before.

Figure 6-18 Pneumothorax.

This CT with IV contrast was performed for evaluation of the mediastinum. Chest CT is not routinely needed for evaluation of pneumothorax. Nonetheless, it reveals several interesting findings. First, despite the chest tube, a pneumothorax remains (remember, air is black on all CT windows), and this was not seen on the supine chest x-ray in Figure 6-17. Why not? The pneumothorax is anterior, so the lung tissue intervening between the x-ray tube and the detector plate prevented recognition of the pneumothorax. The posterior lung tissue is quite dense, and a tiny amount of pleural fluid is present—likely indicating pulmonary contusion and small hemothorax. Alternatively, the posterior lung tissue may be dense resulting from atelectasis. This seems less likely because the left lung does not demonstrate dependent atelectasis. Does the residual pneumothorax require treatment? It will likely resolve with continued use of the existing chest tube, though that chest tube should be examined for kinks and checked for the presence of a continued air leak. When a large pneumothorax persists despite a properly functioning thoracostomy tube, a large airway injury or pulmonary laceration should be suspected.

Figure 6-19 Pneumothorax.

This young male suffered a spontaneous left pneumothorax. The x-ray demonstrates several features typical of pneumothorax and is subtle, though the pneumothorax is relatively large. This pneumothorax appears to be restricted to the left apical region on this upright chest x-ray. There is an absence of lung markings, and the apical thorax appears more lucent than usual resulting from the absence of lung parenchyma. A faint pleural line can be seen. A close-up (Figure 6-20) shows these findings better.

Figure 6-20 Pneumothorax.

Same patient as Figure 6-19, spontaneous apical pneumothorax. The absence of lung markings is clear, and the pleural boundary can be seen.

Figure 6-21 Pneumothorax.

Same patient as Figures 6-19 and 6-20. A, Frontal chest x-ray. B, Close-up from A. Needle aspiration of the pneumothorax was performed, and this x-ray was obtained 6 hours later. A small residual pneumothorax is present (B), although lung markings are now visible above the fifth rib, where they were not previously.

Figure 6-22 Pneumothorax with subcutaneous air on chest x-ray but no visible pneumothorax.

This trauma patient has no visible pneumothorax, with lung markings seen to the periphery. However, subcutaneous air (black) in the lateral left chest wall and neck indicate some form of lung or airway injury, as the patient had no external wounds through which air might have been introduced. Subcutaneous air of this degree, while essentially proving the existence of some respiratory (or less likely, aerodigestive tract) injury, would not mandate CT. For example, in a patient with spontaneous chest pain after cough, CT should not be performed to hunt for associated pneumothorax, although a pneumothorax should be suspected. In this case, chest CT was performed to evaluate for possible thoracic spine injury but incidentally provided more information about the source of the subcutaneous air and is reviewed in Figure 6-23.

Figure 6-23 Small pneumothorax with subcutaneous air on CT with IV contrast.

Same patient as Figure 6-22. A tiny anterior pneumothorax is visible, as well as some dependent pleural fluid, which is likely hemothorax in the setting of trauma. The subcutaneous air is readily visible on lung windows. How should small pneumothoraces seen only on chest CT be managed? Controversy exists (see text). In general, very small pneumothoraces such as this should not be treated. Some authors advocate prophylactic placement of a thoracostomy tube if the patient will be transported long distances, transported by air, or placed on positive-pressure ventilation, which could result in an enlarging pneumothorax. Small studies show a low risk of increasing pneumothorax with positive-pressure ventilation, though this is an obvious complication that must be anticipated.

Figure 6-24 Tension pneumothorax on chest x-ray.

A, The normal chest. B, Schematic of tension pneumothorax. In the case of a tension pneumothorax, a large pneumothorax is typically visible, with a dense-appearing, medially displaced, collapsed lung. Increased pressure results in mediastinal shift and tracheal deviation to the opposite side. The affected side has a depressed hemidiaphragm. If tension pneumothorax occurs on the right side, the right hemidiaphragm may be displaced in a caudad direction and may be lower than the left hemidiaphragm—the reverse of their normal positions. In addition, the costophrenic angle may be extremely deep on the abnormal side (the deep sulcus sign).

Figure 6-25 Tracheobronchial injury with tension pneumothorax.

This 46-year-old male presented unresponsive after a motorcycle collision and was noted to have decreased breath sounds with tachycardia and a blood pressure of 120/80. The patient was intubated and chest x-ray was performed, showing findings concerning for tension pneumothorax. Findings included a large pneumothorax, a dense and medially contracted lung, a deep sulcus sign, a flattened diaphragm, and a shift of the mediastinum to the left. Figure 6-26 shows the patient’s chest x-ray after thoracostomy tube placement. His CT (Figure 6-27) suggested a tracheobronchial injury. Bronchoscopy confirmed transection of the bronchus just distal to the takeoff of the right main bronchus. This was repaired operatively.

Figure 6-26 Tracheobronchial injury with tension pneumothorax.

Same patient as in Figure 6-25. After placement of a right thoracostomy tube, the patient’s findings of tension pneumothorax have resolved.

Figure 6-27 Tracheobronchial injury with tension pneumothorax.

Same patient as in Figures 6-25 and 6-26. This CT with IV contrast suggests but does not prove a tracheobronchial injury. A moderate-size pneumothorax persists despite the right thoracostomy tube, implying that more air is leaking into the pleural space than can be removed by the chest tube. Explanations for this include a large airway injury, a significant pulmonary parenchymal laceration, or a malfunctioning chest tube that is kinked, is plugged, is not attached to suction, or does not have its fenestrations within the pneumothorax. The pneumothorax is visible on the lung window (A) but not on the soft-tissue window (B). Other injuries are present but are discussed separately in other figures—return to this figure later and try to identify pleural fluid (hemothorax), pulmonary contusion, rib fractures, and subcutaneous emphysema. This patient was taken to the operating room, where a bronchial injury was confirmed by bronchoscopy.

Figure 6-28 Tracheobronchial injury with tension pneumothorax.

This 19-year-old female struck a telephone pole and was unresponsive at the accident scene. Emergency medical services providers attempted to decompress a suspected left tension pneumothorax. The patient arrested en route to the emergency department, and on arrival a left chest tube was placed, just before this x-ray. The x-ray shows classic findings of tension pneumothorax, with a deep sulcus sign (so deep that the complete sulcus is not visible on the x-ray). The mediastinum is deviated to the left. The right ribs have assumed an abnormally horizontal position resulting from hyperexpansion of the chest. A left chest tube is present, and extensive subcutaneous air is present (compare with the normal right chest wall). Compare these findings to the CT images in Figure 6-29.

Figure 6-29 Tracheobronchial injury with tension pneumothorax: CT with IV contrast viewed with lung windows.

A, B, Two sequential axial images. Same patient as in Figures 6-28 and 6-30. This CT is highly suggestive of tracheobronchial injury. A right chest tube has been placed and is clearly seen entering the right pleural space. Despite this, a large tension pneumothorax is still present. The mediastinum remains deviated to the left. The most likely explanation is a large airway injury, which would allow air to enter the pleural space faster than it can be removed by a large-bore chest tube. An alternative explanation would be complete occlusion of the chest tube by kinking or internal plugging. The patient is intubated and receiving positive pressure ventilation, increasing the risk that a bronchial injury would result in tension pneumothorax. Massive subcutaneous emphysema has accumulated bilaterally.

Figure 6-30 Tracheobronchial injury with tension pneumothorax.

CT with IV contrast, lung windows. A, Axial CT image. B, Close-up from A. Same patient as in Figures 6-28 and 6-29. The actual tracheobronchial injury is seen. The right main bronchus is seen in direct continuity with the large pneumothorax in right pleural space.

Figure 6-31 Pneumothorax, comparison of chest x-ray and ultrasound findings.

This 19-year-old male had spontaneous right chest pain while playing soccer. This close-up from his chest x-ray shows a moderate apical right pneumothorax. Lung markings are absent at the right apex, and a pleural line is visible.

Ultrasound images from the same patient are shown in Figures 6-32 through 6-34.

Figure 6-32 B mode ultrasound findings of normal lung and pleura.

The normal left lung from the patient in Figure 6-31, viewed with B mode ultrasound. The anterior cortices of two adjacent ribs are visible as echogenic, horizontally oriented curves. Deep to these are acoustic shadows cast by the ribs. Between the ribs lies the horizontal pleural line, a bright white reflection at the interface between the parietal and the visceral pleura. Some authors have described the three lines formed by two adjacent ribs and the pleural line as the bat sign resulting from its resemblance to a stylized line drawing of a bat in flight (diagrammed in figure margin; try to identify this for yourself in the ultrasound image). When real-time ultrasound images are viewed, horizontal motion along the pleural line is normally seen—the sliding lung sign. In the presence of pneumothorax, movement along this line is not seen, as the visceral pleura is separated from the parietal pleura by a buffer of air.

Figure 6-33 M mode ultrasound findings of normal lung and pleura—seashore sign.

Figures 6-31 through 6-34 show images from the same case. Most ultrasound machines allow simultaneous acquisition of a B mode image (A) and an M mode image (B) that represents motion through the line in the B mode image. An M mode image of the normal left lung shows the seashore sign. Motionless tissues superficial to the pleural line have the appearance of a laminated series of horizontal lines, like wave fronts approaching a seashore. Deep to the pleural line, respiratory motion of normal lung gives a granular appearance—the “sand” on the sea shore.

Figure 6-34 M mode ultrasound findings of pneumothorax.

Figures 6-31 through 6-34 show images from the same case. Most ultrasound machines allow a split screen mode, showing B mode (typical two-dimensional images, A) and M mode (motion mode, B) on the same screen. In this figure, a B mode image of the chest wall is seen in the upper portion of the screen, A. An acoustic shadow from a rib is visible, just to the right of the vertical white line. This line has been drawn by the emergency ultrasonographer through the pleura between two ribs. Motion along this line is then depicted in the M mode image in B. The M mode image of the abnormal right lung shows the stratosphere sign, consistent with pneumothorax. Most ultrasound machines allow simultaneous acquisition of a B mode image (A) and an M mode image (B), representing motion through the line in the B mode image.

Figure 6-35 Ultrasound findings of normal lung and pneumothorax.

A lung point sign is simulated in this figure. When an M mode image reveals a transition between the abnormal stratosphere sign and the normal seashore sign, this is called the lung point sign. It is an indication of a partial pneumothorax, with the lung surface intermittently contacting the thoracic wall. Compare with Figures 6-33 and 6-34.

Figure 6-36 Esophageal tear with pneumomediastinum.

CT can demonstrate esophageal injuries following trauma. These are extremely rare following blunt trauma but can occur with penetrating chest trauma. In the case of thoracic gunshot wounds, CT can demonstrate the missile trajectory, indicating its proximity to the esophagus and other mediastinal structures. In addition, focal thickening of the esophagus may be seen at a site of injury. Air leaking from an esophageal injury can create pneumomediastinum visible on CT. In this patient, who has an esophageal injury not from external trauma but from forceful vomiting, the esophagus appears thickened and air is visible surrounding the esophagus (pneumomediastinum). Lung windows reveal air and, in the case of trauma, can reveal a missile trajectory by demonstrating injured lung parenchyma.

Figure 6-37 Pulmonary contusion.

This 77-year-old female was in a car struck by a train. Her chest x-ray shows dense consolidation of the right mid- and lower lung. The costophrenic angle is blunted, and the lateral right diaphragm appears elevated and cannot be distinguished from the consolidation. From Chapter 5, recall the silhouette sign, the principle that two adjacent tissues of the same density cannot be distinguished on chest x-ray. Because the right lateral and lower lung cannot be distinguished from the diaphragm and liver in this patient, they must share the same soft-tissue (fluid) density. Figure 6-38 demonstrates CT images from this patient. Can pulmonary contusion be distinguished from aspiration or other pneumonia? Not based on the chest x-ray findings. Theoretically, this patient could have aspirated—or could have had pneumonia before her collision with the train.

Figure 6-38 Pulmonary contusion.

This 77-year-old female was in a car struck by a train. Compare these CT with IV contrast images with Figure 6-37 showing her chest x-ray. A, Soft-tissue window settings. B, Lung window settings. These images demonstrate that the injured right lung has taken on the same tissue density as muscle tissue—a remarkable transformation of lung to “solid organ.” On soft-tissue window settings, the lung tissue and pectoral muscle appear nearly the same density. The contused lung parenchyma increased in density resulting from alveolar hemorrhage and fluid leaking from injured lung parenchymal cells. Compare with the fairly normal appearance of the left lung on lung windows. Note the different information provided by the two window settings. The lung window setting demonstrates a pneumothorax that is not visible on the soft-tissue window. Incidentally, the anterior right lung shows extensive bullous changes of emphysema, discussed in more detail in Chapter 5.

Figure 6-39 Pulmonary laceration or hemorrhage.

Not all pulmonary injuries are contusions from blunt trauma. This 46-year-old male was shot in the right axilla by police. Bullet fragments are visible in the soft tissues of the right axilla, where a large soft-tissue defect is visible. The lung parenchyma is densely consolidated in the trajectory of the bullet—presumably from bleeding into the damaged tissue. The silhouette sign is again seen; the injured lung parenchyma of the right middle lobe is adjacent to the right heart border and shares the same soft-tissue (fluid) density. As a consequence, the right heart margin is obscured. A chest tube has been placed, and no hemopneumothorax is visible, although the supine position of this chest x-ray reduces its sensitivity for these, as described in an earlier figure.

Figure 6-40 Pulmonary contusion.

This 16-year-old male was a restrained passenger in a motor vehicle collision. He self-extricated and ambulated at the scene but complained of chest pain. His chest x-ray shows a subtle consolidation of the right mid lung. The flexible chest wall of pediatric patients may allow lung contusion without rib fracture.

Figure 6-41 Pulmonary contusion.

Same patient as in Figure 6-40. A, PA chest x-ray. B, Lateral chest x-ray. This chest x-ray was taken 7 hours after the first and shows an evolving pulmonary contusion. Compare with the CT in Figure 6-42.

Figure 6-42 Pulmonary contusion: CT with IV contrast.

Same patient as Figures 6-40 and 6-41. This patient has a subtler pulmonary contusion than does the victim of the car–train collision (Figures 6-37 and 6-38). In those figures, the lung tissue was so densely consolidated that it was easily visible on both chest x-ray and CT soft-tissue windows, with the same apparent density as pectoral muscle. The patient in this figure has less severe injury, with less dense lung tissue in the region of injury. Whereas the injured lung is readily visible on lung windows (A), it is invisible on soft-tissue windows (B). Bilateral pulmonary contusions are visible on CT, whereas the initial x-ray demonstrated only the right-sided contusion clearly.

Figure 6-43 Pulmonary contusion with pneumothorax.

A, AP supine chest x-ray. B, Close-up from A. This 34-year-old male was an unrestrained driver who was thrown through his windshield. His chest x-ray shows a pulmonary contusion with density along the superior right heart border. Careful inspection also reveals a lateral right pneumothorax (B). The width of the upper mediastinum cannot be determined because of the adjacent dense right lung apex. Therefore, CT was performed to evaluate for mediastinal hematoma and aortic injury (Figure 6-44).

Figure 6-44 Pulmonary contusion with pneumothorax.

Same patient as Figure 6-43. A, CT with IV contrast, axial slice viewed with lung windows. B, Same slice, viewed with soft-tissue windows. Some areas of injured lung are densely consolidated and are visible even on soft-tissue windows. Others are less dense, reflecting less alveolar hemorrhage and parenchymal injury—these are visible only on lung windows (A). A small right anterior pneumothorax persists despite the presence of a chest tube, and a small left pneumothorax is present. The pneumothoraces are not visible on soft-tissue windows (B).

Figure 6-45 Pulmonary contusion with pneumothorax.

This 89-year-old male was in a motor vehicle collision in which his airbags deployed. The patient’s chest x-ray shows extensive subcutaneous emphysema of the left chest wall, extending to the left neck. His left lung appears denser than the right, suggesting pulmonary contusion. A small basilar left pneumothorax is difficult to see on this image but is the likely source of the subcutaneous air.

Figure 6-46 Pulmonary contusion with pneumothorax.

Same patient as Figure 6-45, 2 days later. Does this x-ray show progression of pulmonary contusion? It is hard to be sure. The patient has a chest tube in place and may have a hemothorax contributing to increased left lung density. He is intubated, and a ventilator-associated pneumonia may be in progress as well. Upright portable chest x-ray cannot differentiate these causes of increased lung density.

Figure 6-47 Lobar collapse with mediastinal shift resulting from volume loss.

This 38-year-old male was ejected from his vehicle after rolling the car at high speed. (A) His initial chest x-ray shows dramatic mediastinal shift to the right, which in the setting of trauma might first bring to mind left tension pneumothorax. However, mediastinal shift can occur from the “push” of high pressure on the contralateral side (e.g., tension pneumothorax) or from the “pull” of low volume on the ipsilateral side. In this case, the patient has collapse of the right upper lobe, seen as a density in the right lung apex. The minor fissure has tilted diagonally from the accordion-like collapse of the upper lobe, rather than having its normal horizontal configuration. Collapse of the right upper lobe results in volume loss on the right, and the mediastinum shifts right to occupy the resulting space. Was the right upper lobe collapse a traumatic injury? More likely, it represents plugging of the right upper lobe bronchus with mucous or blood. The CT depicting this finding is seen in Figure 6-48. (B) Same patient 2 hours later. The right upper lobe has reexpanded, although density representing atelectasis or possible pulmonary contusion remains. The mediastinum has shifted back toward its normal position. A left chest tube has been placed, as CT did demonstrate a small left pneumothorax—clearly not the cause of the mediastinal shift.

Figure 6-48 Lobar collapse with mediastinal shift resulting from volume loss.

CT with IV contrast viewed on lung windows to best illustrate lobar collapse. Same patient as Figure 6-47, in which his initial chest x-ray shows dramatic mediastinal shift to the right. This is due not to left-sided tension pneumothorax but to significant collapse of the right upper lobe. This results in volume loss on the right, and the mediastinum shifts right to occupy the resulting space. A, An axial slice through the upper chest shows a triangular cross section through the collapsed lung segment. The upper mediastinum has shifted right, and the aortic arch has a nearly right–left transverse orientation rather than an anterior–posterior orientation. A small left pneumothorax is visible as air (black) with no lung markings. B, A coronal view, in which the upper lobe collapse is again visible. The heart and trachea appear shifted right. The left lung does not show any evidence of pneumothorax in this view, though other images show a small pneumothorax. Certainly, a tension pneumothorax was not present and was not the cause of the mediastinal shift.

Figure 6-49 Diaphragm injury.

This 68-year-old female was ejected from a vehicle. Her chest x-ray shows several classic features of diaphragmatic rupture. The right diaphragm is normal in appearance, whereas the left diaphragm is not identified. The patient has an orogastric tube in place, which is coiled in the stomach—in the left lower to midthorax. This is consistent with herniation of the stomach through a diaphragmatic injury into the left thorax. Not specific to diaphragm rupture, the patient also has an indistinct aortic arch, concerning for traumatic aortic injury. The left thorax also appears denser than the right, possibly indicating hemothorax or diffuse pulmonary contusion. Compare with the patient’s CT in Figures 6-50 and 6-51.

Figure 6-50 Diaphragm injury, CT with IV contrast.

CT images from the same patient as Figure 6-49 show the stomach and spleen to be present in the left chest, consistent with a diaphragm rupture. These two images show the same slice, at the level of the left atrium in the chest, on soft-tissue (A) and lung (B) windows. An orogastric tube is seen in the stomach. A portion of the spleen is also seen. On lung windows, no pneumothorax is identified.

Figure 6-51 Diaphragm injury, CT.

CT images from the same patient as Figures 6-49 and 6-50. These two images show the same slice through the chest, on soft-tissue (A) and lung (B) windows. An orogastric tube is seen in the stomach, with an air–fluid level representing gastric contents. The spleen is also seen herniated into the chest with an area of parenchymal contusion. Perisplenic fluid is also seen. On lung windows, no pneumothorax is identified—the area of air is within the stomach.

Figure 6-52 Diaphragmatic rupture.

This 21-year-old male was a rear-seat passenger in a head-on collision with dump truck. Two other passengers were killed at the scene. The patient was noted to have decreased oxygen saturations and no breath sounds. Needle decompression was performed by emergency medical services. This chest x-ray, taken in the emergency department after placement of a chest tube, shows features of diaphragmatic rupture. The normal curvature of the left diaphragm is not seen. The gastric air bubble is seen in the left chest. Note how closely the chest tube passes to the gastric air bubble, a reminder that care should always be taken to assess for solid organs in the chest when placing a chest tube. Not specific to diaphragm rupture, the patient also has opacification of the left hemithorax, which could represent pulmonary contusion or hemothorax on this supine film. In addition, herniation of abdominal contents into the chest can compress lung tissue, giving it this appearance. Compare this x-ray with the CT findings in Figures 6-53 through 6-55. Incidentally, the patient has a severe dextroscoliosis that is not a result of trauma.

Figure 6-53 Diaphragmatic rupture, CT with IV contrast.

Figures 6-52 through 6-55 show images from the same case. A, Soft-tissue windows. B, The same slice viewed on lung windows. In these images near the lung apex, the thoracostomy tube is seen passing into consolidated lung parenchyma. From these images, it is not possible to determine whether this increased density of lung tissue represents contused lung from the original blunt injury or compressive atelectasis from the pressure exerted by herniated abdominal contents. A small anterior pneumothorax is seen on lung windows, despite the chest tube. Fluid density is seen surrounding the lung parenchyma on soft-tissue windows, representing hemothorax.

Figure 6-54 Diaphragmatic rupture.

These CT images are from the same patient as Figures 6-52, 6-53, and 6-55. A, Soft-tissue windows. B, The same slice viewed on lung windows. Here, the stomach is seen in the left chest adjacent to the heart. The air–fluid level represents gastric contents. Note how close to the stomach the thoracostomy tube passes—a reminder to consider diaphragm rupture and to perform a finger sweep when placing a thoracostomy tube for trauma.

Figure 6-55 Diaphragmatic rupture, CT with IV contrast.

Figures 6-52 through 6-55 show images from the same case. A, Soft-tissue windows. B, The same slice viewed on lung windows. Here, the spleen and gastric air bubble are seen adjacent to the heart in the left chest. The right chest appears normal.

Figure 6-56 Thoracic aortic injury.

This patient has a classically abnormal chest x-ray for aortic injury. The mediastinum is wide, the aortic knob and aortopulmonary window are obscured, the trachea and endotracheal tube are deviated by mediastinal hematoma, and the right paratracheal stripe is extremely wide. The patient’s CT is shown in Figure 6-57.

Figure 6-57 Thoracic aortic injury, CT with IV contrast, viewed with soft-tissue windows.

Same patient as Figure 6-56. A, Axial CT image. B, Close-up from A. C, Sagittal CT image.D, Close-up from C. The CT confirms aortic injury with mediastinal hematoma as the cause of the abnormal chest x-ray findings. The mediastinal hematoma surrounds the trachea and esophagus and deviates these to the patient’s right, at the same time creating a wide mediastinum. An aortic intimal injury and pseudoaneurysm are present at the classic location–the insertion site of the ligamentum arteriosum

Figure 6-58 Aortic trauma.

This 29-year-old female was struck by a car and was found unresponsive. Her mediastinum appears wide, and her trachea and orogastric tube are deviated to the right, relative to her thoracic spine. The aortic knob is not clearly seen, and the aortopulmonary window is not seen. These abnormalities can be the result of the mass effect of periaortic hematoma from aortic trauma. The radiology report stated that in this case they likely were resulting from the supine anterior–posterior technique, but CT confirmed aortic injury (Figure 6-59).

Figure 6-59 Aortic trauma, CT with IV contrast viewed with a variation on soft-tissue windows.

Same patient as Figure 6-58. This aortic injury is subtle but definite. Note the irregular contour of the descending aorta, compared with the smooth contour of the ascending aorta. Blood has escaped into the mediastinum, deviating the trachea and esophagus (marked by the orogastric tube) to the patient’s right. The periaortic hematoma also widens the mediastinum. A left hemothorax is present, possibly extending from the aorta. No active extravasation of injected contrast is seen. This is typical of survivors, because patients whose hemorrhage is not initially self-limited often die before reaching the emergency department.

Figure 6-60 Aortic trauma or spontaneous aortic dissection?

This 89-year-old male was in a motor vehicle collision. His chest x-ray is concerning for aortic injury on several accounts. His mediastinum is widened, and the aorta is poorly defined. A left apical pleural cap, an indication of blood escaping from the superior mediastinum, is present (compare with the right lung apex, which appears normal). Although not specific for aortic injury, subcutaneous emphysema is seen in the patient’s left chest wall and neck. His CT is reviewed in Figure 6-61.

Figure 6-61 Aortic trauma or spontaneous aortic dissection?

Same patient as Figure 6-60. A, Axial CT slice through the aortic arch, viewed on soft-tissue windows. B, Axial slice slightly caudad to A, through the ascending and descending aorta. C, Close-up from A. The patient’s CT with IV contrast shows an abnormal aorta, but findings are more typical of a spontaneous aortic dissection than of aortic trauma. Did the patient have an aortic dissection leading to his car collision? We will never know—the patient was moribund on emergency department arrival. He certainly sustained trauma, with other injuries including splenic lacerations and rib fractures. Unlike the aortic traumatic injury in the previous case, there is no periaortic hematoma between the aorta and the trachea. Spontaneous aortic dissections often do not lead to blood loss from the aorta, because the injury involves the intima. The small hemothorax here may emanate from rib fractures.

Figure 6-62 Aortic trauma or spontaneous aortic dissection?

Same patient as Figures 6-60 and 6-61. CT with IV contrast viewed with soft-tissue windows. The descending aorta has an intimal flap, more typical of spontaneous aortic dissection than of traumatic aortic injury. A, At the level of the pulmonary artery, the descending aorta shows thrombosis of the false lumen. B, Farther caudad, contrast is seen in both the true and the false lumen. C, Close-up from B.

Figure 6-63 Aortic trauma.

This 36-year-old female was a restrained passenger in a head-on collision. She had multiple evident injuries on emergency department arrival, including tibial plateau fractures and a pulseless right foot. Her chest x-ray shows an indistinct and somewhat broadened mediastinal contour, although the latter was attributed to the supine anterior–posterior technique. Rib fractures are also visible. Compare with the CT images in Figures 6-64 and 6-65.

Figure 6-64 Aortic trauma, CT with IV contrast.

Same patient as Figures 6-63 and 6-65. A sudden change in aortic caliber is seen on these images, indicating a traumatic aortic injury. Figure 6-65 shows sagittal and three-dimensional reconstructions, demonstrating a pseudoaneurysm. A through C, Consecutive axial CT slices viewed on soft-tissue windows, progressing from cephalad to caudad. D through F, Close-ups from A, B, and C, respectively.

Figure 6-65 Aortic trauma, CT with IV contrast.

Same patient as Figures 6-63 and 6-64. A, Sagittal CT planar reconstruction, viewed on soft-tissue windows, depicting the aorta from its root through the arch and into the descending aorta. B, Three-dimensional reconstruction of the same region, with other thoracic structures digitally removed. The tiny image in the right lower corner of panel B is an axial cross-section inserted automatically by 3D software for orientation purposes. A, R, L, and P in that image indicate anterior, right, left, and posterior. These reformats are not necessary to make the diagnosis of traumatic aortic pseudoaneurysm but do help indicate the extent and assist with surgical planning. The patient underwent endovascular repair.

Figure 6-66 Aortic trauma.

This 18-year-old man was involved in a severe motor vehicle collision. Among his many injuries were an open-book pelvis fracture and shock bowel. His chest x-ray shows an elevated left hemidiaphragm consistent with diaphragm rupture. His mediastinum is indistinct and shifted to the right, worrisome for aortic injury—which was confirmed on CT (Figures 6-67 and 6-68). Look carefully at the position of the endotracheal tube and gastric tube—both are shifted to the right. The right paratracheal stripe is also wide. These features are concerning for mediastinal hematoma, possibly from aortic injury. The patient developed multiorgan failure and died on hospital day 2.

Figure 6-67 Aortic trauma, CT with IV contrast, axial images viewed with soft-tissue windows.

Same patient as Figures 6-66 and 6-68. Moving from cephalad (A) to caudad (C), note the change in aortic caliber. The enlarged region in B is a pseudoaneurysm. The patient has multiple other chest injuries, including a diaphragm rupture with the stomach in the left chest and a large right hemothorax.

Figure 6-68 Aortic trauma, CT with IV contrast.

Figures 6-66 and 6-67 show images from the same case. This reconstruction in a parasagittal plane shows an area of traumatic pseudoaneurysmal dilatation. This can be recognized on the axial images (Figure 6-67) as a sudden change in aortic diameter.

Figure 6-69 Aortic trauma.

This 20-year-old male struck a tree with his car and was hypotensive during emergency transport. His chest x-ray shows the now-familiar findings of a widened mediastinum, wide right paratracheal stripe, deviated trachea and gastric tube, indistinct aortic knob, and lack of the normal pulmonary artery window, consistent with traumatic aortic injury. See CT images, Figures 6-70 and 6-71, and aortogram, Figure 6-72.

Figure 6-70 Aortic trauma, CT with IV contrast, axial image viewed with soft-tissue window.

Same patient as Figure 6-69. The aortic injury itself is not seen, but periaortic hematoma is present, deviating the trachea and gastric tube (within the esophagus) to the right, just as was seen on chest x-ray. Figure 6-71 shows the aortic injury.

Figure 6-71 Aortic trauma, CT with IV contrast.

Figures 6-69 through 6-72 depict the same case. A, Axial CT slice viewed with soft-tissue windows. B, Close-up from A. More caudad, the descending aorta has an irregular contour and internal filling defects, indicating both an internal tear and a pseudoaneurysm formation. Compare with the angiogram from the same patient in Figure 6-72.

Figure 6-72 Aortic trauma.

Figures 6-69 through 6-72 show images from the same case. The patient underwent an aortogram, confirming an aortic pseudoaneurysm. Note the similarity to the appearance on CT reconstructions from the prior cases. No active extravasation of contrast is seen. The patient’s injury was repaired using endovascular stents.

Figure 6-73 Aortic trauma.

A 26-year-old male was shot just left of the sternum. The bullet crossed the midline, coming to rest in the right axilla. This chest x-ray demonstrates complete opacification of the right chest, consistent with a large hemothorax, as well as possible underlying pulmonary contusion. Subcutaneous air is visible in the right chest wall. The aortic knob is not clearly defined, raising the question of a mediastinal injury. The patient underwent CT (Figures 6-74 and 6-75).

Figure 6-74 Aortic trauma CT with IV contrast.

Figures 6-73 through 6-76 depict other images from the same case. A, Axial CT slice, viewed with soft-tissue windows. B, The same slice, viewed with lung windows. C, Close-up from A. The bullet has tracked across the anterior mediastinum, resulting in a left anterior pulmonary contusion, an anterior mediastinal hematoma, and apparent dissection of the ascending aorta with an intimal flap. The left pulmonary contusion, anterior mediastinal hematoma, and right posterior pulmonary contusion all contribute to the appearance of the wide mediastinum and obscured aortic knob on chest x-ray. The patient underwent thoracotomy and intraoperative ultrasound, in which the intimal flap seen on CT was thought to represent artifact. No aortic repair was performed. The ascending aorta is subject to motion artifacts on CT that can simulate aortic dissection. Electrocardiogram-gated CT can eliminate this motion artifact to allow more accurate evaluation.

Figure 6-75 Aortic trauma, CT with IV contrast.

Same patient as Figures 6-73, 6-74, and 6-76. A, Axial CT slice, viewed with soft-tissue windows. B, The same slice, viewed with lung windows. Note how different window settings reveal different information from the same anatomic region.

Figure 6-76 Aortic trauma.

This sagittal CT reconstruction from the same patient as Figures 6-73 through 6-75 also appears to show an intimal flap of the ascending aorta. Intraoperative ultrasound was felt to be negative for dissection. Motion artifact at the aortic root can cause false positive findings. ECG gating (discussed in Chapter 8) can eliminate this artifact.

Figure 6-77 Aortic trauma.

This 34-year-old male was riding a motorcycle when he was struck by an oncoming car. His chest x-ray demonstrates multiple abnormalities, including a left clavicle fracture and left first rib fracture, and increased density of both hemithoraces, suggesting possible pulmonary contusion. The left diaphragm is not clearly seen, which may indicate a layering hemothorax on this supine chest x-ray. Diaphragm rupture can also result in an indistinct diaphragm. Air is visible, tracking in the left neck and outlining the superior mediastinum. The heart and mediastinum appear slightly deviated to the right side. The aortic knob is not clearly seen. The patient’s chest CT is reviewed in Figures 6-78 and 6-79.

Figure 6-78 Aortic trauma.

Figures 6-77 through 6-80 depict the same case. A, Axial CT slice, viewed with soft-tissue windows. B, Close-up from A. On the patient’s initial CT with IV contrast, only a single slice revealed a possible aortic injury. A transverse filling defect suggested an intimal flap where the aorta passes the pulmonary artery—the location of the ligamentum arteriosum. Coincidence? This was suspected to be artifact, and repeat CT with finer cuts was performed (Figure 6-79).

Figure 6-79 Aortic trauma.

A, Axial CT slice, viewed with soft-tissue windows. B, Close-up from A. Repeat CT showed the same appearance of a transverse filling defect at precisely the same level as in Figure 6-78, proving an aortic injury. This injury is at the level of the ligamentum arteriosum, which once connected the pulmonary artery and aorta. Coronal and sagittal reconstructions are shown in Figure 6-80.

Figure 6-80 Aortic trauma, CT with IV contrast.

Figures 6-77 through 6-80 depict the same case. A, Sagittal CT reconstruction, viewed with soft-tissue windows. B, Coronal CT reconstruction. C, Close-up from A. These reconstructions confirm an aortic injury at the level of the ligamentum arteriosum, which once connected the pulmonary artery and aorta. Endovascular repair was performed.

Figure 6-81 Aortic trauma.

This 46-year-old male was found unconscious and hypothermic in a car that had crashed at an unknown time. His core temperature was 31°C. The patient was found in the passenger seat and was unrestrained. His chest x-ray shows a wide mediastinum with no distinct aortic knob. The right paratracheal stripe is wide. These findings could be the result of a mediastinal hematoma from aortic injury. CT was performed (Figure 6-82 and 6-83), followed by aortography (Figure 6-84).

Figure 6-82 Aortic trauma.

A CT with IV contrast (axial image, soft-tissue window) from the same patient as Figure 6-81 demonstrates an irregular aortic contour and a small amount of periaortic hematoma just anterior to the aorta. Figure 6-83 shows two slightly oblique reconstructions that further define this injury.

Figure 6-83 Aortic trauma, CT with IV contrast.

Figures 6-81 through 6-84 explore the same case. A, Sagittal CT image, soft-tissue window. reconstruction from the same patient demonstrates an irregular aortic contour and a small amount of periaortic hematoma (dark gray, soft-tissue density on these soft-tissue windows) just anterior to the aorta. B, The area of injury begins with a narrowed region (pseudocoarctation) and progresses into a dilated area (pseudoaneurysm). Aortogram was performed (Figure 6-84).

Figure 6-84 Aortic trauma.

Figures 6-81 through 6-84 explore the same case. Aortogram from the patient demonstrates the same configuration of pseudocoarctation and pseudoaneurysm. An aortic stent graft was placed.

Figure 6-85 Aortic trauma.

This 29-year-old male was an unrestrained driver in a high-speed motor vehicle collision. His injuries included a hip dislocation, femur fracture, and open tibia fracture.

The patient’s chest x-ray shows deviation of the trachea to the right, which we have seen can be the effect of a mediastinal hematoma from aortic injury. The mediastinum does not appear especially wide, but the aortic knob is indistinct. In addition, there is suggestion of an apical pleural cap. Some of these features may be a result of supine position and the patient’s rotation to the right. The patient’s chest x-ray after intubation supports the concern for mediastinal hematoma (Figure 6-86).

Figure 6-86 Aortic trauma.

Same patient as Figure 6-85. The patient has now been intubated, and an orogastric tube has been placed. The orogastric tube is also deviated to the right, suggesting a mediastinal hematoma. The right paratracheal stripe is also wide. The patient’s CT scan is reviewed in Figures 6-87 and 6-88.

Figure 6-87 Aortic trauma, CT with IV contrast.

Same patient as in Figures 6-85 and 6-86. Consecutive axial CT images viewed with soft-tissue windows. A through H descend from cephalad to caudad. In B, a defect resembling an intimal flap is seen. C through F, An irregularity projects into the lumen from the posterior aortic wall.

Figure 6-88 Aortic trauma.

Same patient as in Figures 6-85 through 6-87. A, a defect resembling an intimal flap is seen. B, the aorta resumes its normal size and smooth internal contour.

Figure 6-89 Aortic trauma, CT with IV contrast.

Figures 6-85 through 6-89 explore the same case. A through H here are close-ups from panels A through H in Figures 6-87 and 6-88. They are taken from consecutive axial CT images through the region of the descending thoracic aorta, viewed with soft-tissue windows.A to H descend from cephalad to caudad. Periaortic hematoma and irregularities of the descending aorta are seen.

Figure 6-90 Aortic trauma.

This 17-year-old male was found outside of his vehicle at 4:15 AM. In the emergency department, he was unresponsive, with fixed and dilated pupils and priapism. The patient is intubated and bilateral chest tubes have been placed. Both lungs show increased density, suggesting pulmonary contusion. The gastric tube is deviated to the right, and the aortic knob is indistinct. A black line surrounds the heart, suggesting pneumomediastinum. Fractures of the first and second ribs were also noted, although they are hard to see in this image. CT was performed (Figures 6-91, 6-92).

Figure 6-91 Aortic trauma, CT with IV contrast.

A through D, Consecutive axial CT slices through the thorax, viewed with soft-tissue windows. A through D descend from cephalad to caudad. E, Close-up from B. F, Close-up from C. A CT from the same patient as Figure 6-90 shows a focal defect in the posterior wall of the descending aorta, visible only on two consecutive slices. This is a traumatic pseudoaneurysm. Figure 6-92 shows this in sagittal reconstructions.

Figure 6-92 Aortic trauma, CT with IV contrast.

A, Sagittal CT reconstruction from the same patient as in Figures 6-90 and 6-91 shows a focal defect in the posterior wall of the descending aorta. This is a traumatic pseudoaneurysm. B, Close-up from A. Both images are viewed with soft-tissue windows.

Figure 6-93 Aortic trauma.

This 30-year-old male fell from a tower while doing electrical work—an estimated 20 to 50 feet. He complained of back and abdominal pain, as well as dyspnea. Notably, he had no palpable pulses in his lower extremities. His chest x-ray was interpreted as normal—the trachea is not deviated, the mediastinum is not wide for a supine x-ray, and the aortic knob and descending aorta are clearly visible. His CT is shown in Figures 6-94 through 6-98.

Figure 6-94 Aortic trauma: Abdominal aorta.

A, The patient’s scout CT image is telling—a significant step-off is visible at the L1-2 level. Remember that the abdominal aorta lies just anterior to the spinal column at this level. B, Close-up from A. Figure 6-95 examines axial CT slices.

Figure 6-95 Aortic trauma: Abdominal aorta, CT with IV contrast.

Figures 6-93 through 6-98 depict the same case. A, The abdominal aorta appears nearly normal, but already a very large bilateral retroperitoneal hematoma is visible (soft-tissue density, gray on these soft-tissue windows), extending posterior to both kidneys. This abnormality is seen in all of the slices shown but labeled only in A. B to D, A blush of contrast (white) indicating active extravasation of injected contrast is visible adjacent to the aorta. E, F, and G at right are close-ups from B, C, and D, respectively.

Figure 6-96 Aortic trauma: Abdominal aorta.

Figures 6-93 through 6-98 depict the same case. Continuation of Figure 6-95. A, The abdominal aorta is identifiable, with active extravasation and a large retroperitoneal hematoma. Blood that had collected before CT appears soft-tissue density (gray), whereas actively extravasating blood is mixed with contrast and appears white. By B to D, the aorta is a tiny remnant vessel. D, The double image of the vertebral body is not artifact—this is the level of the subluxation of L1 on L2, and both vertebrae are seen. E, Close-up from A. F, Close-up from B. G, Close-up from D.

Figure 6-97 Aortic trauma: Abdominal aorta, CT with IV contrast.

Figures 6-93 through 6-98 depict the same case. A to H, Sagittal CT reconstructions reveal both the spinal subluxation and the major aortic injury. Remarkably, the patient survived and was able to walk with a rolling walker despite some spinal cord injury.

Figure 6-98 Aortic trauma: Abdominal aorta, CT with IV contrast.

Other images from the same patient are shown in Figures 6-93 through 6-97. A, Sagittal reconstruction viewed with soft-tissue windows reveals both the spinal subluxation (L1 on L2) and the major aortic injury. The abdominal aorta reconstitutes below the level of transection but has a smaller diameter. B, Close-up from A. Remarkably, the patient survived and was able to walk with a rolling walker despite some spinal cord injury.

Figure 6-99 Aortic trauma.

This 54-year-old female was an unrestrained passenger in a car that struck a tree. Her chest x-ray shows a wide mediastinum with deviation of the trachea. The gastric tube, which appears nearly midline at the top of the x-ray, deviates to the right upon entering the mediastinum, suggesting possible mediastinal hematoma. The aortic knob is not well defined. These findings could indicate aortic injury. Other trauma findings in this patient include a left clavicle fracture, multiple right rib fractures, a right chest tube with subcutaneous air in the right chest wall, and pneumopericardium. This last finding is indicated by the visible inferior and left heart borders. The inferior border of the heart is not normally seen, because it is fluid density and lies in direct contact with the diaphragm, also fluid density. In this case, air in the pericardial sac provides contrast. Compare with the CT (Figure 6-100).

Figure 6-100 Aortic trauma, CT with IV contrast.

Same patient as in Figure 6-99. Consecutive axial CT images viewed with soft-tissue windows, descending from A through H. The images show periaortic hematoma (soft-tissue density, gray) surrounding the aortic arch and deviating the trachea and esophagus to the patient’s right. A focal defect in the distal aortic arch is visible—a traumatic pseudoaneurysm. E, Close-up from B. F, Close-up from C. Figure continues in Figure 6-101.

Figure 6-101 Aortic trauma.

Additional images for the same patient are shown in Figures 6-99 through 6-104. A-D, The circumferential periaortic hematoma extends distally around the uninjured portion of the descending aorta. This hematoma continues to deviate the esophagus and gastric tube, as was seen on chest x-ray.

Figure 6-102 Aortic trauma, CT with IV contrast.

Additional images for the same patient are shown in Figures 6-99 through 6-104. A, Sagittal CT reconstruction using soft-tissue windows shows the pseudoaneurysm as an irregularity on the inferior aspect of the distal aortic arch. B, Close-up from A.

Figure 6-103 Aortic trauma, CT with IV contrast.

Additional images for the same patient are shown in Figures 6-99 through 6-104. These coronal images show the periaortic hematoma and traumatic pseudoaneurysm. A to C move from anterior to posterior. B, C, The aorta does not have the normal smooth and rounded contour. In all three images, circumferential periaortic hematoma is present. On these soft-tissue windows, hematoma is gray, similar to skeletal muscle.

Figure 6-104 Aortic trauma.

Additional images for the same patient are shown in Figures 6-99 through 6-104. This aortogram demonstrates the pseudoaneurysm. Although aortography has been the historical gold standard for this diagnosis, CT can give more three-dimensional information. This pseudoaneurysm appears relatively small in this image, because a portion of it extends posterior to the opacified aortic arch and is hidden in this projection. During aortography, usually several projections are obtained from different angles to overcome this limitation.

Figure 6-105 Apical pleural cap.

An apical pleural cap is a finding associated with traumatic aortic injury. It is a soft-tissue (fluid) density at the lung apex, which can represent blood tracking out of the superior mediastinum and above the pleural surface of the lung apex.

This 48-year-old male struck a car on his motorcycle. His chest x-ray shows an apical pleural cap on the left—compare with the normal right apex. He also has left-sided rib fractures. CT did not show an aortic injury; an apical pleural cap is a nonspecific finding, though it warrants further study with CT in the setting of significant trauma.

Figure 6-106 Apical pleural cap.

This 25-year-old male rolled his car and was transported by emergency medical services. His chest x-ray shows a possible apical pleural cap, as well as a poorly defined aortic knob. Follow-up CT did not show an aortic injury.

Figure 6-107 Gunshot wound to back with bullet adjacent to aorta.

This 22-year-old male was shot in the posterior thorax just left of midline. He complained of back and abdominal pain. His supine chest x-ray shows radiopaque bullet fragments left of the thoracic spine. The x-ray is otherwise unremarkable. CT was performed to localize the bullet (Figure 6-108).

Figure 6-108 Gunshot wound to back with bullet adjacent to aorta, CT with IV contrast.

A, Axial CT slice viewed with soft-tissue windows. B, The same slice, viewed with lung windows. C, Close-up from A. This CT from the same patient as in Figure 6-107 shows three bullet fragments, marked by metallic streak artifact. One lies immediately subcutaneously. The second is within paraspinal muscle exterior to the bony thorax. The third lies immediately adjacent to the aorta. Streak artifact makes complete evaluation of the aorta impossible, but no significant hematoma surrounds the aorta. The adjacent lung shows contusion but no hemopneumothorax.

This patient was observed briefly and did not undergo further imaging to evaluate the aorta. However, aortography could have been used to assess this injury. Unlike CT, aortography is not subject to metallic streak artifact and could have identified irregularity of the aorta near the bullet fragment.

Figure 6-109 Pneumomediastinum.

This 18-year-old college student developed chest pain while lying in bed. He had no history of trauma, cough, or vomiting but had played basketball earlier in the day. His chest x-ray shows the typical subtle findings of pneumomediastinum. The white line paralleling the left heart border is the pericardium—the lucent region between the pericardium and the left heart border is air within the pericardial sac. Some vertically oriented lucent areas are seen in the upper mediastinum as well. The inferior border of the heart is not outlined with air in this case, although air may be seen in that location. What was the source of the air? No pneumothorax is seen, but perhaps the patient performed the Valsalva maneuver during his basketball game and forced air from the respiratory tree into the mediastinum. Compare with his lateral chest x-ray (Figures 6-110 and 6-111). His CT images are reviewed in Figures 6-112 and 6-113, although arguably CT was unnecessary. The patient recovered uneventfully.

Figure 6-110 Pneumomediastinum.

Same patient as in Figures 6-109 and 6-111. A, The lateral chest x-ray shows some subtle findings of pneumomediastinum. B, Close-up from A. A faint black line (air) marks the anterior surface of the heart. In addition, normally no interface can be seen between the inferior heart border and the diaphragm, because they share the same x-ray density. However, a lucent line marks the inferior heart border here, indicating air in the pericardium.

Figure 6-111 Pneumomediastinum.

Figures 6-109 through 6-113 explore this case with x-ray and CT.

Figure 6-112 Pneumomediastinum.

Figures 6-109 through 6-113 explore this case with x-ray and CT. This CT image (lung windows) high in the mediastinum just inferior to the carina shows air outlining the heart anteriorly, as well as air posterior to the heart, including outlining the aorta.

Figure 6-113 Pneumomediastinum.

Same patient as in Figures 6-109 through 6-112. Figures 6-109 through 6-113 explore this case with x-ray and CT. A, This computed tomography image (lung windows) lower in the mediastinum shows air (black) outlining the aorta and esophagus—areas where no air should be found. B, Close-up from A.

Figure 6-114 Knife wound to chest.

This 33-year-old male presented with a self-inflicted stab wound to the left chest. His chest x-ray shows a wide mediastinum. The left costophrenic angle is blunted, suggesting hemothorax, despite a left thoracostomy tube. This tube is badly positioned, as one of the fenestrations is not in the pleural space. A knife overlies the heart apex, though a single x-ray view cannot determine whether it lies within the patient. Given the wide mediastinum, a cardiac injury with blood in the mediastinum is possible. The right upper lobe is dense with cephalad retraction of the minor fissure, indicating right upper lobe collapse. CT was performed (Figures 6-115 and 6-116)

Figure 6-115 Knife wound to chest.

CT scout images from the patient in Figures 6-114 and 6-116. Given both the frontal (A) and the lateral (B) scout images, the knife is buried to the handle in the patient’s chest.

Figure 6-116 Knife wound to chest, CT without IV contrast.

Same patient as Figures 6-114 and 6-115. Lung windows. These CT images show the trajectory of the knife to skirt the pericardium. As a result of metal artifact, the precise location of the knife cannot be judged. No large pericardial effusion is seen. The CT was performed without intravenous contrast, so extravasation of contrast from the heart cannot be definitively ruled out. A small anterior pneumothorax is seen. Some dependent pleural fluid is visible. The patient underwent thorascopic surgery that showed no cardiac injury.

Figure 6-117 Knife wound to chest.

This 23-year-old male presented with a self-inflicted stab wound to the left chest. He was hemodynamically stable and alert, with the knife in place in the left chest wall, on emergency department arrival. Bedside echocardiography did not demonstrate a pericardial effusion. A portable chest x-ray was obtained. This x-ray demonstrates the importance of two orthogonal views when determining the location of a foreign body. A, The anterior–posterior (AP) view shows the knife to overlie the left chest, although in theory the knife could be outside of the patient, either behind or in front of his torso. B, In the lateral projection, the depth of penetration of the knife is revealed, although the position of the knife is not certain—in theory, it could lie outside of the patient to the left or right of the thorax. A, The anterior–posterior (AP) view shows the location to overlie the left chest, although in theory the knife could be outside of the patient, either behind or in front of his torso. Together, these views confirm a deep central stab wound to the chest. On the AP view, the knife appears to contact the left heart border, but penetration of the pericardium or heart is uncertain. A CT was obtained to delineate the knife’s position in greater detail (Figures 6-118 through 6-120). If the knife did not penetrate the pericardium, it could be removed at bedside, rather than requiring thoracotomy.

Figure 6-118 Knife wound to chest.

Figures 6-117 through 6-120 explore this case using x-ray and CT. Scout images from the CT reveal the same information depicted on chest x-ray (Figure 6-117). A, Frontal scout image. B, Lateral scout image.

Figure 6-119 Knife wound to chest, CT with IV contrast.

Figures 6-117 through 6-120 include additional images from this case. A and C, Consecutive axial soft-tissue windows. B and D, Lung windows of the same axial slices shown in A and C, respectively. Soft-tissue windows show the knife tip to lie within the lateral wall of the left ventricle. There is no pericardial effusion. Remarkably, lung windows show no pneumothorax, although a small hemothorax is seen. In this case, CT provided important clinical information that determined patient management. X-ray (Figure 6-117) suggested an injury tangential to the heart, which could possibly have been managed nonoperatively by removal of the knife in the trauma bay. CT prompted thoracotomy. Intraoperatively, the patient had brisk myocardial bleeding that could have resulted in pericardial tamponade if a pericardial window had not been created.

Figure 6-120 Knife wound to chest.

Figures 6-117 through 6-119 include additional images from this case. The knife tip is seen in the lateral wall of the left ventricle on this close-up CT image. Contrast is not seen to escape the ventricle.