Microbubbles at the bedside: intracavitary CEUS to confirm chest-drain position and loculations

Background: CEUS is increasingly used beyond hepatobiliary imaging; its pleuro-pulmonary applications remain limited, especially for device assessment. Case description: We describe a postoperative patient with moderate right pleural effusion and associated middle–basal atelectasis causing hypoxemic respiratory failure. After ultrasound-guided insertion of a 12-Fr pigtail drain, the catheter trajectory and tip could not be confidently visualized due to limited patient mobilization and small-bore caliber. A second-generation UCA (sulfur hexafluoride) diluted 1 mL in 10 mL saline was instilled through the drain. CEUS immediately demonstrated contrast egress from the catheter tip, confirming intrapleural position, and opacified the effusion, delineating the pleural cavity and the atelectatic lung. Enhancement dissipated within ~ 4 min. The drain was then left on gravity with an anti-reflux valve; no adverse events occurred. Conclusion: Intrapleural CEUS via an indwelling chest drain is a rapid, bedside, radiation-free method to confirm catheter placement and map loculations, potentially improving interventional safety and follow-up.