Visualization of the secondary pulmonary lobeles with 0.5-mm multidetector CT

The pulmonary lobule is a structural unit that is composed of pulmonary parenchyma measuring 1 cm or less in size and which has been the basis for the morphological evaluation of diffuse pulmonary diseases or isolated shadows in the lung. Using multidetector CT (MDCT) with a 0.5-mm slice thickness, it is possible to obtain so-called ''isotropic'' voxels, in which the spatial resolution is the same in the x, y, and z axes. Accordingly, images reconstructed in any desired sectional plane can have nearly the same spatial resolution as the original axial HRCT images. This article describes new methods for the visualization of the pulmonary lobular structure using MDCT with a slice thickness of 0.5 mm. Because the interlobular septa are well developed in the subpleural region, the two imaging methods described below were used for the examination of the subpleural region. The subpleural region is displayed as a curved surface below an arbitrarily voxel on the curved pleural surface. This method is suitable for the visualization of widespread, diffuse pathological changes. After the slice direction has been set so that it is parallel to the pleural surface, a plane 2 to 5 mm below the pleural surface is displayed. This method is suitable for the assessment of circumscribed areas and localized pathological processes. (author)