Esophageal cancer is a common malignant tumor of the digestive tract. Surveys show that the annual global incidence of esophageal cancer is 455,800, while the annual death toll is 400,200 [7, 8]. Esophageal resection remains the preferred treatment for resectable esophageal cancer . Typically, extensive resection of esophageal cancer and intrathoracic anastomosis of the aortic arch or neck are performed to replace the esophagus with the stomach. The thoracic stomach runs on the original esophageal bed of the posterior mediastinum that is adjacent to the trachea, carina, and main bronchus. The TGAF is formed by abnormal communication between the thoracic stomach and the airway because of the poor anastomotic technique of the esophagus and stoma, infection in the anastomotic area, tumor recurrence, radiation-induced lesions, and ischemia. The mortality rate soared due because of repeated pulmonary infections and malnutrition .
Following esophagogastric anastomosis, patients experience remained gastric ulcer  due to bile reflux, gastric emptying disorder, ischemia, radiation therapy, and tumor recurrence. After gastric perforation, the perforation area communicates with the airway. Gastric juice is highly acidic and contains several digestive enzymes that spill through the fistula into the alkaline environment of the airway and lung, thereby resulting in chemical, corrosive, digestive pneumonia and secondary pulmonary infection. The patient may experience an irritating cough-like burning which is a typical characteristic of TGAF, because the symptom aggravates in a supine position and alleviates while being seated, in anteversion or semi-seated. We named this clinical manifestation as Burning-like Cough Syndrome in Recumbent Position.
Traditional upper gastrointestinal radiography can locate the fistula; however, after oral administration of the contrast agent, it enters the airway through the fistula and aggravates the symptoms of cough and pulmonary infection, thereby limiting the presentation of atelectasis, inflammation, and pleural effusion. Compared with upper gastrointestinal radiography, MSCT is a common non-invasive imaging examination method that offers the advantages of being non-irritating and not aggravating pulmonary infection in addition to having a high spatial resolution. At the same time, MSCT can observe and analyze images in multi-window width, multi-window position, and multi-plane and can fully generalize the pathological changes .
In this study, MSCT could clearly display the fistula in 192 patients with TGAF and had a positive detection rate of 88.9%. The negative results seen in 24 patients may likely be attributed to the small size of the fistula, circuitous course, or inflammation and edema at the fistula, but gastrointestinal radiography, bronchoscopy or gastroscopy verified the existence of the fistula. MSCT can display the location of the fistula and measure its size on multiple levels. It can also measure the length and diameter of the trachea and bronchus to provide effective reference data for the next treatment of airway-stent placement [12, 13]. Based on the location of the thoracogastric fistula and its communication with the airway as revealed by MSCT, we can divide TGAF into six types: ⑴ TGAF: thoracogastric communicates with the trachea; ⑵ Thoracogastric carina fistula: thoracogastric fistula communicates with carina area (within 2 cm of carina and its upper part); ⑶ Thoracogastric left main bronchial fistula: thoracogastric fistula communicates with the left main bronchus; ⑷ Thoracogastric right main bronchial fistula: thoracogastric fistula communicates with the right main bronchus; ⑸ Thoracogastric right middle main bronchial fistula: thoracogastric fistula communicates with the right middle main bronchus; and ⑹ Thoracogastric bronchiole fistula: thoracogastric fistula communicates with the bronchioles on the left or right lung surface.
MSCT can distinctly show the pulmonary infection. However, the pulmonary infection in patients with TGAF varies and is not specific. However, 95.8% of the cases have patchy high-density shadows along the lung texture, which is distributed mostly in the lower lobe of the lung and is closely related to the location of the fistula. 48.1% of the cases suffered from pulmonary consolidation due to aggravated infection, which was characterized by a large high-density shadow of the lung lobe and air bronchogram in some lesions. Obstructive atelectasis may occur when viscous secretions or gastric contents block the trachea, bronchus, or trachea and bronchial wall owing to inflammatory stimulation and edema, resulting in narrowing or occlusion of the corresponding lumen, which is characterized by large dense shadows similar to the corresponding lobes. Pleural effusion was noted as a complication in 43.9% of the cases; pericardial effusion, in 43.5%; and pleural hypertrophy, in 85.1%. MSCT could also detect whether patients with TGAF had further complications of primary pulmonary diseases such as chronic bronchitis, emphysema, pulmonary interstitial fibrosis, and bronchiectasis .
MSCT can detect tumor recurrence and distant metastasis in patients with esophageal cancer after operation. In this study, 25 patients showed complications of anastomotic wall and chest gastric wall thickening, and contrast-enhanced scan of the same could be seen in varying degrees of enhancement. At such times, clinicians should suspect tumor recurrence. Twenty-three patients had distant metastasis. Therefore, MSCT can comprehensively elucidate the clinical changes in patients and provide more comprehensive information for optimum treatment.
In conclusion, if irritating cough occurs after esophagectomy with esophagogastric arch or cervical anastomosis, TGAF should be suspected and interpreted to improve the prognosis . MSCT can provide direct visual confirmation of the fistula, and it can also find other lesion features providing reliable imaging data for clinical diagnosis and treatment.