Direct and indirect CT imaging features of esophago-airway fistula in adults

Background Esophago-airway fistula (EAF) is an abnormal connection between the esophagus and the trachea or a major bronchus. While contrast esophagography remains the primary radiographic tool for the diagnosis of EAF, computed tomography (CT) is often employed in its evaluation. A systematic analysis of CT findings of EAF in adults has not been previously published. The goal of our study is to determine the direct and indirect CT findings of EAF in adults. Methods We identified patients with EAF detected on CT at our institution between January 1, 2001 and December 31, 2019, with endoscopic or surgical confirmation. We collected patient clinicopathologic characteristics and assessed CTs for direct and indirect imaging features of EAF in these patients. Results Twenty-six patients (median age: 56 years; range, 25-79 years; F=13, 50% and M=13, 50%) with confirmed EAF were identified. Half of the patients had an underlying malignancy. On CT, a direct connection between the esophagus and the airway was identified in most cases (22/26; 85%). Common indirect CT findings of EAF included esophageal wall thickening (21/26, 81%), mediastinal fatty stranding (21/26, 81%), airway wall thickening (20/26, 77%), fluid or debris within the airways (17/26, 65%), and focal or diffuse esophageal dilation with air (17/26, 65%). Mediastinal fluid collections were infrequently seen (4/26, 15%), but findings of aspiration or other pneumonia were common (19/26, 73%). Conclusions CT plays an essential role in both the primary and secondary evaluation of adult EAF resulting from both malignant and benign etiologies. CT may be the first diagnostic exam to suggest and detect the presence of EAF and may precede clinical suspicion, and it can detect a subset of fistulas not demonstrated on esophagography. There are several direct and indirect imaging findings on CT that can help in the detection of EAF.