Unveiling tracheo-oesophageal fistula: The crucial role of imaging in the diagnosis and management

SA Journal of Radiology ISSN: (Online) 2078-6778, (Print) 1027-202X Page 1 of 7 Review Article Unveiling tracheo-oesophageal fistula: The crucial role of imaging in the diagnosis and management Authors: Poonam Sherwani1 Nivedita Sharma1 Rajat Piplani2 Ekakshi Varshney1 Sumit Kumar3 Tracheo-oesophageal fistula (TOF) is a significant congenital anomaly characterised by an abnormal communication between the trachea and the oesophagus. Prompt diagnosis and surgical intervention are crucial, but long-term outcomes depend on accurate imaging and postoperative monitoring. The article discusses the embryological basis, clinical presentation and various types of TOF with their imaging techniques. Immediate and long-term postoperative complications are also discussed. Recent advances such as Ultrashort Echo Time (UTE), MRI and the Oesophageal Anastomotic Stricture Index (OASI) have expanded the capabilities of imaging in predicting surgical outcomes and guiding follow-up. Affiliations: 1 Department of Diagnostic and Interventional Radiology, All India Institute of Medical Sciences (AIIMS), Rishikesh, India Contribution: This review highlights the pivotal role of imaging in the diagnosis, classification, surgical planning and follow-up of TOF, focusing on current and emerging modalities. Department of Pediatric Surgery, All India Institute of Medical Sciences (AIIMS), Rishikesh, India 2 Department of Radiology and Imaging, Govind Ballabh Pant Institute of Postgraduate Medical Education and Research (GPIMER), Delhi 3 Corresponding author: Poonam Sherwani, poonam.rd@aiimsrishikesh. edu.in Dates: Received: 26 May 2025 Accepted: 25 July 2025 Published: 23 Sept. 2025 How to cite this article: Sherwani P, Sharma N, Piplani R, Varshney E, Kumar S. Unveiling tracheooesophageal fistula: The crucial role of imaging in the diagnosis and management, S Afr J Rad. 2025;29(1), a3216. https://doi.org/10.4102/sajr. v29i1.3216 Copyright: © 2025. The Authors. Licensee: AOSIS. This work is licensed under the Creative Commons Attribution License. Read online: Scan this QR code with your smart phone or mobile device to read online. Keywords: contrast oesophagogram; oesophageal stricture; tracheo-oesophageal fistula; ultrashort echo time MRI; VACTERL association; fistulous; foregut. Introduction Congenital tracheo-oesophageal fistula (TOF) is one of the most frequently encountered congenital abnormalities in common clinical practice. The term describes a condition where there is a persistent fistulous communication between the trachea and the oesophagus. Infants usually present with breathing and feeding difficulties with an associated risk of aspiration. Various imaging modalities such as radiographs, contrast swallow studies, CT and MRI are required for the diagnosis as well as to look for complications; however, the choice of modality should be individualised based on the clinical scenario. In this review article, the role of various imaging modalities will be described along with their benefits and drawbacks. Embryology and types of tracheo-oesophageal fistula During early gestation, the lung bud arises from the ventral aspect of a single embryological foregut. Subsequently, the trachea and oesophagus develop distally through a process of septation, wherein the trachea forms as a diverticulum from the foregut. A mesenchymal septum progressively separates the trachea from the oesophagus. Abnormal posterior displacement of this septum results in incomplete separation of the two structures, leading to a persistent TOF.1,2 This process is tightly regulated in both spatial and temporal dimensions by the notochord, which modulates Sonic Hedgehog (SHH) gene expression. Disruption in this signalling pathway can result in defective tracheo-oesophageal separation, often in association with other anomalies comprising the VACTERL spectrum (vertebral, anal, cardiac, tracheo-oesophageal, renal and limb anomalies).1 Congenital TOFs are classified into types A to E based on the Gross classification: • • • • • Type A: Pure oesophageal atresia (OA) without a fistula. Type B: OA with a proximal TOF. Type C: OA with a distal TOF (most common type). Type D: OA with both proximal and distal fistulas. Type E (H-type or N-type): TOF without OA.3 A fistulous tract connects the trachea and oesophagus without associated OA, often resembling the shape of the letter “H” or “N” on imaging. From a surgical perspective, types A and B are particularly challenging because of the presence of a long gap between the proximal and distal oesophageal segments and are thus referred to as http://www.sajr.org.za Open Access Page 2 of 7 long-gap OA. A schematic representation of the various TOF types is illustrated in Figure 1. Clinical presentation The classic presentation of OA at birth is an infant who exhibits excessive mucous and drooling because of saliva pooling in the blind-ending upper oesophageal pouch. Infants displaying these signs should not be fed until OA has been definitively excluded. Additional clinical indicators include tachypnoea, coughing and choking during attempts to feed. Approximately one-third of infants with OA are born prematurely, and maternal polyhydramnios is reported in about 30% of cases – this incidence is notably higher in infants without a distal TOF. The presence of associated anomalies known to occur with OA should raise clinical suspicion. For instance, in cases with polyhydramnios or anorectal malformations, the patency of the oesophagus should be assessed early by attempting to pass an orogastric tube shortly after birth.1 The incidence of TOF is 2.9 per 10 000 worldwide. It is generally diagnosed when the clinician is unable to insert a feeding tube. Diagnosis of TOF is usually made clinically, however, imaging is required in doubtful cases and in H-shaped fistula. Radiographs are the preliminary investigation performed to look for air in the stomach and associated anomalies in the spine. When the components of the VACTREL complex are detected, a detailed and thorough investigation should be made to evaluate for the rest, which includes a meticulous clinical examination and necessary imaging. Type B Type A Type C Review Article Air in the stomach is present when there is fistulous communication between the lower oesophagus and trachea (Types C, D and E), in which cases the clinical diagnosis is usually straightforward. Radiological investigations play an important role not only in determining the type of TOF and aiding its management but also in diagnosing the postoperative complications of TOF repair, including oesophageal strictures, recurrence of TOF, tracheomalacia and reflux. Imaging Antenatal examination Radiologically, TOF can be determined antenatally through ultrasound at approximately the 20th week of gestation. The demonstration of a dilated oesophagus or pouch oesophagus on swallowing is the most important finding and has 100% positive predictive value.4 Post (...truncated)