Intralobar sequestration. Demonstration of collateral ventilation by nuclear lung scan.

An intralobar pulmonary sequestration in the left lower lobe was studied before and after surgical excision. Ventilation scans showed delayed entry and subsequent trapping of radiogas in the area of sequestration. High pressure injection of barium sulfate in the left lower lobe bronchus, however, revealed no connection of the bronchial tree to the sequestration. The ventilation scan is a useful method to demonstrate collateral ventilation to a pulmonary sequestration.