Thoracic ultrasound in the diagnosis of malignant pleural effusion N R Qureshi, 1 N M Rahman, 2 F V Gleeson 3 See Editorial, p 97 c Additional details of the techniques, statistical analysis and figures are published online only at http://thorax.bmj.com/ content/vol64/issue2 1 Department of Radiology, Papworth Hospital NHS Foundation Trust, Papworth Everard, Cambridge, UK; 2 Oxford Centre for Respiratory Medicine and University of Oxford, Oxford Radcliffe Hospital, Oxford, UK; 3 Department of Radiology, Oxford Radcliffe Hospital, Oxford, UK Correspondence to: Dr F V Gleeson, Department of Radiology, Oxford Radcliffe Hospital, Headington, Oxford OX3 7LJ, UK; fergus.gleeson@ nds.ox.ac.uk NRQ and NMR are joint first authors with equal roles in design, delivery and publication. Received 29 June 2008 Accepted 23 September 2008 Published Online First 13 October 2008 ABSTRACT Background: 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. A study was undertaken 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, diaphrag- matic 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 by a second blinded operator using anonymised TUS video clips. The TUS diagnosis was compared with the definitive clinical diagnosis and in addition to the diagnosis found at CECT. Results: A 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 .1 cm, pleural nodularity and diaphragmatic thickening .7 mm were highly suggestive of malignant disease. Conclusion: TUS is useful in differentiating malignant from benign pleural disease in patients presenting with suspected MPE and may become an important adjunct in the diagnostic pathway. Investigation of pleural effusion of unknown aetiology is well described in British, American and European guidelines. 1–3 These guidelines and other papers 4 recommend clinical evaluation, basic radiological investigation and diagnostic pleural fluid sampling in the majority of unilateral pleural effusions. Malignancy remains the most common cause of unilateral pleural effusion in the UK and USA, with an estimated 250 000 new cases of malignant pleural effusions per year. 25 Cytology- positive pleural fluid is found in 60% of cases of malignant pleural effusion, 1 6–8 with a substantially lower positive rate in mesothelioma, 9 and further investigations to establish diagnosis are recom- mended in the context of cytology-negative uni- lateral pleural exudates. 1–4 10 Thoracic CT scanning with contrast enhancement (contrast-enhanced CT, CECT) is a sensitive and specific test for malignant pleural disease, 11 with morphological criteria established in previous studies. 12 13 CECT is recommended as the next investigation, with a view to subsequent histological diagnosis (blind, image-guided or thoracoscopic pleural biopsy). 4 14 Thoracic ultrasound (TUS) is a valuable clinical tool which is increasingly being performed by chest physicians. In the UK, guidelines have recently been published with suggested training for physi- cians with an interest in practising TUS. 15 Hitherto, the role of TUS has been limited to pleural fluid detection (with high sensitivity) and image-guided techniques (thoracocentesis, drain placement, lung biopsy). 14 The sonographic appearance of malignant pleural effusion and the value of ultrasound in determining the nature of pleural effusion have been described in previous studies. 16 17 However, there are no published studies to our knowledge which have assessed the diagnostic accuracy of ultrasound for malignancy in patients with sus- pected but undiagnosed malignant pleural effusion. The primary aims of this study were therefore (1) to assess the sensitivity and specificity of ultrasound in the detection of malignant disease in patients with suspected malignant pleural effusion using established morphological criteria from CECT; and (2) to investigate the use of other morphological characteristics on TUS associated with malignant pleural disease. In addition, the overall TUS diagnostic rate and CECT diagnostic rate were compared, in comparison to a definitive clinical diagnosis for malignant effusion. METHODS Subjects The study was undertaken in a tertiary referral centre for respiratory/pleural disease and involved consecutive patients presenting with unilateral pleural effusion of unknown aetiology from both inpatient and outpatient settings. Inclusion criteria c Chest radiograph evidence of pleural effu- sion(s). c No established diagnosis (malignant or other- wise) of the cause of pleural effusion. c The patient would in normal clinical practice undergo further investigations to establish the cause of pleural effusion. Exclusion criteria c A clinical and/or histological diagnosis had been established. c Clinical and radiographic features of empyema. Pleural disease Thorax 2009;64:139–143. doi:10.1136/thx.2008.100545 139 group.bmj.com on April 17, 2016 - Published by http://thorax.bmj.com/ Downloaded from