Ratwani, Ankush P., Grosu, Horiana B., Husnain, Shaikh Muhammad Noor Ul, Sanchez, Trinidad M., Yermakhanova, Gulmira, Pannu, Jasleen Kaur, Debiane, Labib Gilles, DePew, Zachary S., Yarmus, Lonny B., & Maldonado, Fabien. (2025). Post-thoracentesis ultrasound versus chest radiography for the evaluation of effusion evacuation and lung reexpansion: A multicenter study. Annals of the American Thoracic Society, 22(9). https://doi.org/10.1513/AnnalsATS.202410-1095OC
This study compared two imaging methods—ultrasound and chest X-ray (CXR)—to see how well they assess whether fluid has been fully removed from the pleural space after thoracentesis, a procedure that drains fluid around the lungs. Patients with free-flowing pleural effusions were enrolled, and after the procedure, an ultrasound was performed immediately, while a CXR was done within four hours. The main outcome was whether both methods agreed on complete pleural space evacuation, defined as no remaining fluid seen on ultrasound or no blunting of the costophrenic angle on CXR.
A total of 145 patients were analyzed, with a median age of 64 years, and cancer was the most common cause of fluid buildup. The lung was considered trapped in half of the patients. More than 800 ultrasound images were reviewed independently by pulmonologists and radiologists who did not know the patient or procedure details. The results showed very strong agreement between ultrasound and CXR (agreement coefficient 0.93, 95% CI 0.83–1.00). When comparing based on effusion size, there was substantial agreement (kappa 0.64, 95% CI 0.51–0.77). Agreement between proceduralists and blinded ultrasound reviewers was also strong (kappa 0.81, 95% CI 0.71–0.90).
In conclusion, post-thoracentesis ultrasound is an equally effective alternative to chest X-ray for evaluating pleural space evacuation in patients with simple pleural effusions.
Figure 1.Pre and postthoracentesis evaluation of pleural effusion using ultrasound and chest radiography (CXR). (A) Large free-flowing simple pleural effusion visible in the posterior view. (B, C) Effusion size measured in the anterior and midaxillary views. (D) Prethoracentesis CXR with a pleural effusion (arrow). (E–G) Post-thoracentesis images showing resolution of the effusion and complete pleural evacuation in the midaxillary, anterior, and posterior views. (H) Post-thoracentesis CXR with complete pleural evacuation.