Fig 2. CT fistulogram. Axial CT images (kV = 120, mA = 120, thickness = 1.25 mm) without intravenous contrast are shown from superior (A) to inferior (F). Contrast material is seen within the first branchial cleft tract (arrow). The relationships of the tract to the parotid gland and the retromandibular vein (arrowhead) are well defined for ease of surgical planning. A, Contrast is seen spilling into the external auditory canal (E). B, Just below the external auditory canal, the tract passes into the parenchyma of the parotid gland. C, The tract traverses the gland, running superficial to the retromandibular vein. D, Streak artifact from dental amalgam degrades the image as the tract passes through the parotid capsule into the subcutaneous fat. E, The tract continues inferiorly within the subcutaneous fat. F, The tract exits the skin at the level of the mandibular angle.