Thoracic Ultrasound in the diagnosis of Malignant Pleural Effusion

Nagmi R Qureshi ¹, Najib M Rahman ² and Fergus V Gleeson ^3*

¹ Papworth Hospital NHS Foundation Trust, United Kingdom
² Oxford Centre for Respiratory Medicine, Oxford University, United Kingdom
³ Oxford Radcliffe Hospitals, United Kingdom

^* To whom correspondence should be addressed. E-mail: fergus.gleeson{at}nds.ox.ac.uk.

Accepted 23 September 2008

Abstract

Rationale: Malignant pleural effusion (MPE) is a common clinical problem with described investigation pathways. While thoracic ultrasound (TUS) has been shown to be accurate in pleural fluid detection, its use in the diagnosis of malignant pleural disease has not been assessed.

Objectives: To assess the diagnostic accuracy of TUS in differentiating malignant and benign pleural disease.

Methods: 52 consecutive patients with suspected MPE underwent TUS and contrast enhanced CT (CECT). TUS was used to assess pleural surfaces using previously published CT imaging criteria for malignancy, and diaphragmatic thickness/nodularity, effusion size/nature and presence of hepatic metastasis (in right sided effusions). A TUS diagnosis of malignant or benign disease was made blind to clinical data / other investigations, and by a second blinded operator using anonymised TUS video clips. TUS diagnosis was compared to definitive clinical diagnosis, and in addition to the diagnosis found at CECT.

Results: Definitive malignant diagnosis was based on histocytology (30/33 (91%)) and clinical / CT follow up (3/33 (9%)). Benign diagnoses were based on negative histocytology and follow up over 12 months in 19/19 patients. TUS correctly diagnosed malignancy in 26/33 patients (sensitivity 73%, specificity 100%, Positive Predictive Value 100%, Negative Predictive Value 79 %) and benign disease in 19/19. Pleural thickening >1cm, pleural nodularity and diaphragmatic thickening >7mm were highly suggestive of malignant disease.

Conclusion: TUS is useful in differentiating malignant from benign pleural disease in patients presenting with suspected malignant pleural effusion and may become an important adjunct in the diagnostic pathway.