Concentric and bottleneck airway obstruction

Concentric airway obstruction (A) is a narrow ring-like area of obstruction that involves a short segment of the airway as opposed to bottleneck obstruction (B and C) which involves a longer segment with tapering superiorly and inferiorly. Bottleneck lesions are less likely to be responsive to balloon dilation since they are more likely to be associated with loss of supporting cartilage.