Endobronchial valves are one-way valves that restrict airflow to a particular lung segment. The devices are inserted via bronchoscopy. They permit the drainage of airway secretions during the expiratory phase but restrict incoming airflow during inspiration .
They were originally designed as an alternative to surgery for lung volume reduction in cases of severe emphysema. They have also been used to treat bronchopleural and bronchoalveolar fistulas with persistent air-leaks .
Commonly used devices are the Spiration Intrabronchial Valve System® and the Zephyr ® Endobronchial Valve, both are MRI conditional at field strengths less than 3 T .
Small radiopaque markers and struts overlying an airway will be visible. Atelectasis distal to the valve should usually also be visible .
Potential complications include :