Studies of paranasal sinus ventilation by xenon-enhanced dynamic CT.

A new method to determine ventilation of the paranasal sinuses is presented. After insufflation of pure stable xenon into the sinus system via the nasal cavity the gas wash-out is detected by means of quantitative dynamic computerized tomography. The measured time density curves allow to derive gas exchange parameters for all paranasal sinuses. We report mean gas exchange times for the maxillary, sphenoidal and frontal sinuses as well as the posterior ethmoidal cells obtained from 17 patient studies. Some clinical examples are discussed in detail. Compared to existing procedures, xenon-enhanced dynamic CT is the only non-invasive quantitative method to determine ventilation of all paranasal sinuses.