CT imaging of the normal bronchial system

Imaging of the normal bronchial system by CT was examined in 75 patients while employing different imaging parameters. The main and lobar bronchi could be demonstrated almost without exception in the standard examination of the thorax. Segmental bronchi were delineated in an average of 81% of the cases (512 image matrix) or 74% (256 image matrix) respectively. The lowest identification rate was seen in the segmental bronchi of the middle lobe and lingula being 38% (512 image matrix) and 18% (256 image matrix), respectively. Increase in the identification rate of the segmental bronchi of the middle lobe and lingula was achieved only after reducing the slice thickness from 8 mm to 4 mm, the yield being now 87% (512 image matrix) and 82% (256 image matrix), respectively, whereas the remaining segmental bronchi could be made to show up almost without exception. The standard parameters are sufficient for routine examination of the bronchial system. If imaging is diagnostically not satisfactory, reducing the slice thickness yields improved imaging, especially of small bronchi. (orig.)