Dynamic computed tomography of the lung: Regional ventilation measurements

The spatial resolution provided by computed tomography (CT) yields excellent anatomic specificity, and fast scanners are capable of the serial imaging necessary to monitor rapid changes in tracer concentration over time. In this study, sequential CT imaging defined the temporal changes of xenon concentration in peripheral lung tissue of a nonhuman primate and three sheep, both during and after xenon inhalation. Ventilation rate constants (K) in lung tissue with normal and impaired function were assessed and compared. Limitations and potential solutions involved in the evaluation of regional ventilation using xenon enhanced CT are discussed.