Quantitative 3D CT bronchography

In the framework of computer-aided diagnosis, this paper proposes a novel functionality for computerized tomography (CT)based investigation of pulmonary airways. It provides a specific visualization modality - the virtual CT bronchography - together with quantitative investigation via a central axis-based description. This functionality relies on an energy-based 3D reconstruction of the bronchial tree up to the 6th order divisions. The originality of the 3D reconstruction approach consists in combining axial and radial propagation potentials in a growth-driven process, which is applied to a subset of low-order airways extracted from the CT volume by means of a robust mathematical morphology operator. The tree central axis, which provides the navigation and quantification functionalities, is computed via a recursive procedure applied to each bronchial segment, based on geodesic front propagation. Validated by expert radiologists, examples of virtual CT bronchographies are presented for both normal and pathological airways and the interest of quantitative CT bronchography in clinical diagnosis and follow-up is discussed.