Purpose or Case Report: Branchial apparatus anomalies (BAA) due to aberrations in the development and involution of the branchial apparatus can present as a cyst, fistula, or sinus tract. Definitive treatment for a BAA is complete surgical excision. The embryology of BAA has been well described, but few reports in the published literature discuss optimally imaging these patients. The purpose of this study is to describe the CT and MR imaging findings of BAA, and to correlate the imaging findings with surgery and pathology results. The goal is to develop a standardized imaging approach and search pattern specific to each subtype of BAA that would answer the most pertinent clinical questions for surgical planning.
Methods & Materials: All patients less than 18 years of age with proven BAA by surgical or pathology findings and preoperative CT or MR imaging performed between January 1, 2006 and February 28, 2015 were identified by searching our electronic medical records. Two observers (1 pediatric neuroradiologist, 1 pediatric radiology fellow) recorded the imaging findings, including anomaly type, size, extent and the presence of a cyst, fistula or sinus tract. The findings were correlated with clinic notes, operative reports, and pathology results.
Results: Fifty patients with surgically proven BAA and preoperative CT or MRI were identified. Of these, 19 had a first BAA, 18 had second BAA, and 13 had a third or fourth BAA. A total of 33 contrast enhanced CT and 25 MRI were reviewed, with 8 patients having both a CT and a MRI. CT was 88% sensitive and MRI was 96% sensitive for the detection of BAA. For all BAA, 72% (26 of 36) of fistulas were identified preoperatively, with 58% (14 of 24) identified on CT and 93% (14 of 15) identified on MRI. Approximately 53% of patients with a first BAA had involvement of the parotid gland, with 100% of cases identified on CT (3 of 3) and 57% identified on MRI (4 of 7). For third and fourth BAAs, 8 patients had thyroid gland involvement with 100% of cases detected on both CT and MRI, and 7 had pyriform sinus involvement with 100% of cases detected on CT (4 of 4) and 80% of cases detected on MRI (4 of 5).
Conclusions: Preoperative imaging provides vital information for surgical planning by defining the type and extent of BAA. CT and MRI are both sensitive for the detection of a BAA and determining involvement of adjacent head/neck structures. Overall, MRI is more sensitive for determining the presence of a fistula or sinus tract, although CT fistulagram can be valuable in selected cases.