3D segmentation of the airway tree using a morphology based method

Segmentation of the airways is useful for the analysis of airway compression and obstruction caused by pathology. This paper outlines an automatic method for segmentation of the airway tree. This method includes algorithms to detect the trachea, segment the trachea and main bronchi by thresholding and region growing, and segment the remaining bronchi by morphological filtering and reconstruction. Morphological filtering and reconstruction are applied to all slices in the axial, sagittal and coronal planes and are used to extract the smaller airways. Bounded space dilation with a leak removal restriction is applied as a region growing method. This method was evaluated on 20 cases as part of the MICCAI pulmonary image analysis workshop. The mean number of branches detected as a percentage of possible branches was 43.5%, the mean tree length detected as a percentage of the entire tree length was 36.4% and the false positive rate – that is, the percentage of the total volume that was incorrectly segmented – was 1.27%