- Irreversible bronchial dilitation from chronic infection
- Secondary to proximal airway obstruction (infection) or congenital abnormaility (cystic fibrosis, marfan's syndrome, kartagener's syndrome)
- Larger than accompanying pulmonary artery, signet ring sign
- Lack of tapering or bronchi within 1cm of pleura.
- Cylindric, varicose or cystic forms correspond to mild, moderate and severe
Upper Lobe - CF, ABPA Anterior - MAC Unilateral - infectious Low Lobe - ciliary diskinesia, immune deficiency, aspiration