Figure 1b. Images from a thoracic CT angiographic study performed with a 16–detector row scanner. (a) Axial 1-mm-thick CT scan obtained just below the aortic arch (window center, 50 HU; window width, 350 HU) shows enlarged bronchial arteries (arrow) manifesting as avidly enhancing nodules in the paratracheal and retrobronchial regions of the mediastinum. These findings represent the typical appearance of enlarged bronchial arteries on axial images. Although the origins of the bronchial arteries are well depicted on axial images, their further course is very tortuous, and the intrapulmonary direction of the artery can be difficult to ascertain. (b) Coronal thin-section MIP image clearly demonstrates an enlarged intercostobronchial artery (arrows) coursing into the pulmonary parenchyma parallel to the bronchial airways. (c) Coronal thin-section MIP image obtained in a different patient provides a detailed analysis of the entire intrapulmonary course of an intercosto-bronchial artery (arrows). 
= intracavitary mycetoma. (d) Reformatted image demonstrates how CT angiography can provide anatomic information that is useful for planning subsequent bronchial artery embolization.