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3. Intravenously contrast-enhanced chest CT followed by repeat CT using orally administered intravenous contrast
Any form of CT- unenhanced or enhanced with injection of intravenous contrast using either an aortography or pulmonary angiography protocol- would be useful for assessment of this patient, but employing a CT protocol specifically tailored to assess for esophageal injury that can simultaneously assess the lungs, aorta, and pleural space would be the optimal approach. Such a protocol initially employs intravenously enhanced CT imaging (without oral contrast) to detect pneumomediastinum- esophageal injury should show this finding, and the absence of pneumomediastinum should exclude significant esophageal perforation. Additionally, this protocol can simultaneously evaluate the aorta, lungs, and pleural space for the various alternative causes of chest pain that could clinically simulate esophageal injury. If no pneumomediastinum is detected, further imaging is not required. If pneumomediastinum is found, then oral contrast is administered. Generally when esophageal injury is present, water-soluble contrast media is utilized in the event perforation has occurred; the use of barium in this situation is generally avoided owing to fears of the potential development of granulomatous mediastinitis if the barium contrast material gains access to the mediastinum. However, the commonly employed water-soluble contrast agent used for upper gastrointestinal examinations is hyperosmolar, and inadvertent aspiration of this substance can lead to pulmonary edema. Therefore, diluted intravenous contrast material is an excellent oral contrast agent to employ when using CT to assess for esophageal injury because the contrast agents used for intravenous contrast injections cause little reaction if aspirated and are generally inert should they reach the mediastinal tissues. This dilute, orally administered intravenous contrast material is given just prior to a separate second CT acquisition- if the pneumomediastinum seen on the first acquisition fills with the orally administered contrast agent, the diagnosis of esophageal perforation is established.
Lateral decubitus CT may show findings suggesting esophageal injury, namely pneumomediastinum- but the lateral decubitus position is not of particular benefit for esophageal assessment. Lateral decubitus CT has been suggested as a useful technique to demonstrate air trapping [in the dependent lung] for patients who cannot properly cooperate with the breathing instructions required for supine post-expiratory imaging.
The patient underwent chest CT using the specific esophageal protocol described above (Figure 2).
Figure 2. A-F: Representative images from the CT esophagram following the intravenous injection of contrast material but prior to the oral administration of dilute intravenous contrast material. G-L: Representative images from the CT esophagram following the oral administration of dilute intravenous contrast material. Lower left: Video of the CT esophagram following the intravenous injection of contrast material. Lower right: Video of the CT esophagram following the oral administration of dilute intravenous contrast material.
Which of the following represents the most accurate assessment of the chest CT findings? (Click on the correct answer to proceed to the ninth and final page)