Bronchial artery branching pattern evaluation. A sagittal section of a thoracic CT scan which is used to evaluate the vertebral level of the bronchial artery origin of the bronchial arteries is shown (dashed line). A branching pattern of the bronchial arteries from a common trunk (one right and one left) originating from the aortic arch is also shown. CTB = common trunk of the bronchial arteries, RBA = right bronchial artery, and LBA = left bronchial artery.