Three-dimensional CT of the bronchial tree. A trial using an inflated fixed lung specimen.

Three-dimensional (3D) reconstruction of the bronchial tree from contiguous scanning of thin-section CT was performed. Automatic extraction of the bronchial inner space was tried by means of thresholding CT numbers, using a left lower lobe obtained at autopsy and fixed in the air-filled state. Anatomic accuracy of the reconstructed 3D image was determined by correlating the image with the sliced lung specimen. Because of the partial volume effects of the bronchial walls, the area in which bronchi could be reconstructed was limited. The smallest reconstructed branch was 1.4 mm in inner diameter, and the spatial relationship among the branches was easily understood.