Digital subtraction ductography.

Digital subtraction techniques used in the examination of eight patients with salivary and nasolacrimal disease are described. Pleomorphic adenoma, ductal stricture, extrinsic masses, parotid-otic fistula, and a radiolucent calculus were demonstrated. The procedures are more easily performed than film techniques, and pathology is better demonstrated by digital ductography than on a film examination. Image subtraction, reregistration, and window manipulation allowed clear demonstration of ducts about the head and neck, overcoming limitations imposed by inherently high object contrast. Digital subtraction ductography is an important nonvascular application of digital imaging technology.