should be used instead of water‐soluble contrast agents, because these hyperosmolar agents may cause severe pulmonary edema if a fistula is present [140].
Esophagopleural fistulae may be caused by esophageal carcinoma, radiation therapy, surgery, or instrumentation [140]. Such patients may present with a pleural effusion, pneumothorax, or hydropneumothorax. When an esophagopleural fistula is suspected, the presence and location of the fistula can be confirmed by a study with water‐soluble contrast agents.
Aortoesophageal fistulae are extremely rare but are associated with a high mortality rate. Such fistulae may be caused by a ruptured aortic aneurysm, aortic dissection, infected aortic graft, swallowed foreign body, or esophageal carcinoma [142]. Patients with aortoesophageal fistulae may present with an initial episode of arterial hematemesis followed by a variable latent period, before experiencing massive hematemesis, exsanguination, and death [142]. Oral studies with water‐soluble contrast agents are unlikely to show the fistula because of high aortic pressures, whereas contrast aortography may fail to show the fistula because of occlusion of the fistulous tract by thrombus [142].
Figure 6.79 Esophageal carcinoma with esophagobronchial fistula. A barium study shows an advanced infiltrating squamous cell carcinoma in the mid esophagus (straight arrows) with barium entering the airway via an esophagobronchial fistula (curved arrow).
Perforation
If untreated, perforation of the thoracic esophagus is associated with a mortality rate of nearly 100% because of a fulminant mediastinitis that occurs in these patients [140]. Early diagnosis is therefore critical. Endoscopy is the most common cause of esophageal perforation, accounting for up to 75% of cases [140]. Other causes include foreign bodies, food impactions, penetrating and blunt trauma, and spontaneous esophageal perforation resulting from a sudden, rapid increase in intraluminal esophageal pressure (Boerhaave’s syndrome).
Cervical esophageal perforation may be manifested on neck or chest radiographs by subcutaneous emphysema, retropharyngeal air, and pneumomediastinum [140]. Lateral radiographs of the neck may also show widening of the pre‐vertebral space or a retropharyngeal abscess containing loculated gas or air–fluid levels. In contrast, thoracic esophageal perforation may be associated with pneumomediastinum, mediastinal widening, and a pleural effusion or hydropneumothorax [140]. In the proper setting, the presence of mediastinal gas on CT should be highly suggestive of esophageal perforation, whereas other findings such as a pleural effusion or mediastinal fluid are less specific [140]. However, CT is unreliable for determining the site of perforation.
Figure 6.80 Esophageal perforation after traumatic endoscopy. A study with a water‐soluble contrast agent shows focal extravasation of contrast from the right lateral wall of the mid esophagus (open arrows) into the right side of the mediastinum (closed arrows).
Esophagography is often performed on patients with suspected esophageal perforation. Some patients have free leaks into the mediastinum (Figure 6.80), whereas others have small, sealed‐off leaks. Although barium is the most sensitive contrast agent for detecting small leaks, it can potentially cause a granulomatous reaction in the mediastinum. In contrast, water‐soluble agents do not incite a mediastinal reaction and are readily absorbed from the mediastinum if a leak is present. However, water‐soluble contrast agents are less radiopaque than barium and can miss a substantial percentage of esophageal perforations [140]. It is therefore recommended that the examination be repeated with barium to detect subtle leaks if the initial study with a water‐soluble contrast agent shows no evidence of perforation [140].
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