Pleural disease Thoracic ultrasound in the diagnosis of malignant Thorax: first published as 10.1136/thx.2008.100545 on 13 October 2008. Downloaded from pleural effusion N R Qureshi,1 N M Rahman,2 F V Gleeson3 See Editorial, p 97 ABSTRACT criteria established in previous studies.12 13 CECT is Background: Malignant pleural effusion (MPE) is a c Additional details of the recommended as the next investigation, with a techniques, statistical analysis common clinical problem with described investigation view to subsequent histological diagnosis (blind, and figures are published online pathways. While thoracic ultrasound (TUS) has been image-guided or thoracoscopic pleural biopsy).414 only at http://thorax.bmj.com/ shown to be accurate in pleural fluid detection, its use in Thoracic ultrasound (TUS) is a valuable clinical content/vol64/issue2 the diagnosis of malignant pleural disease has not been tool which is increasingly being performed by chest 1 Department of Radiology, assessed. A study was undertaken to assess the physicians. In the UK, guidelines have recently Papworth Hospital NHS diagnostic accuracy of TUS in differentiating malignant been published with suggested training for physi- Foundation Trust, Papworth 15 Everard, Cambridge, UK; and benign pleural disease. cians with an interest in practising TUS. 2 Oxford Centre for Respiratory Methods: 52 consecutive patients with suspected MPE Hitherto, the role of TUS has been limited to Medicine and University of underwent TUS and contrast-enhanced CT (CECT). TUS pleural fluid detection (with high sensitivity) and Oxford, Oxford Radcliffe was used to assess pleural surfaces using previously image-guided techniques (thoracocentesis, drain Hospital, Oxford, UK; placement, lung biopsy).14 3 Department of Radiology, published CT imaging criteria for malignancy, diaphrag- Oxford Radcliffe Hospital, matic thickness/nodularity, effusion size/nature and The sonographic appearance of malignant Oxford, UK presence of hepatic metastasis (in right-sided effusions). pleural effusion and the value of ultrasound in A TUS diagnosis of malignant or benign disease was determining the nature of pleural effusion have Correspondence to: made blind to clinical data/other investigations by a been described in previous studies.16 17 However, Dr F V Gleeson, Department of Radiology, Oxford Radcliffe second blinded operator using anonymised TUS video there are no published studies to our knowledge Hospital, Headington, Oxford clips. The TUS diagnosis was compared with the definitive which have assessed the diagnostic accuracy of OX3 7LJ, UK; fergus.gleeson@ clinical diagnosis and in addition to the diagnosis found at ultrasound for malignancy in patients with sus- nds.ox.ac.uk CECT. pected but undiagnosed malignant pleural effusion. NRQ and NMR are joint first Results: A definitive malignant diagnosis was based on The primary aims of this study were therefore authors with equal roles in histocytology (30/33; 91%) and clinical/CT follow-up (1) to assess the sensitivity and specificity of design, delivery and publication. (3/33; 9%). Benign diagnoses were based on negative ultrasound in the detection of malignant disease Received 29 June 2008 histocytology and follow-up over 12 months in 19/19 in patients with suspected malignant pleural Accepted 23 September 2008 patients. TUS correctly diagnosed malignancy in 26/33 effusion using established morphological criteria http://thorax.bmj.com/ Published Online First patients (sensitivity 73%, specificity 100%, positive from CECT; and (2) to investigate the use of other 13 October 2008 predictive value 100%, negative predictive value 79%) and morphological characteristics on TUS associated benign disease in 19/19. Pleural thickening .1 cm, with malignant pleural disease. In addition, the pleural nodularity and diaphragmatic thickening .7mm overall TUS diagnostic rate and CECT diagnostic were highly suggestive of malignant disease. rate were compared, in comparison to a definitive Conclusion: TUS is useful in differentiating malignant clinical diagnosis for malignant effusion. from benign pleural disease in patients presenting with on September 30, 2021 by guest. Protected copyright. suspected MPE and may become an important adjunct in METHODS the diagnostic pathway. Subjects The study was undertaken in a tertiary referral Investigation of pleural effusion of unknown centre for respiratory/pleural disease and involved aetiology is well described in British, American consecutive patients presenting with unilateral and European guidelines.1–3 These guidelines and pleural effusion of unknown aetiology from both other papers4 recommend clinical evaluation, basic inpatient and outpatient settings. radiological investigation and diagnostic pleural fluid sampling in the majority of unilateral pleural Inclusion criteria effusions. Malignancy remains the most common c Chest radiograph evidence of pleural effu- cause of unilateral pleural effusion in the UK and sion(s). USA, with an estimated 250 000 new cases of c No established diagnosis (malignant or other- 25 malignant pleural effusions per year. Cytology- wise) of the cause of pleural effusion. positive pleural fluid is found in 60% of cases of c 1 6–8 The patient would in normal clinical practice malignant pleural effusion, with a substantially undergo further investigations to establish the 9 lower positive rate in mesothelioma, and further cause of pleural effusion. investigations to establish diagnosis are recom- mended in the context of cytology-negative uni- lateral pleural exudates.1–4 10 Thoracic CT scanning Exclusion criteria with contrast enhancement (contrast-enhanced c A clinical and/or histological diagnosis had CT, CECT) is a sensitive and specific test for been established. malignant pleural disease,11 with morphological c Clinical and radiographic features of empyema. Thorax 2009;64:139–143. doi:10.1136/thx.2008.100545 139 Pleural disease Thorax: first published as 10.1136/thx.2008.100545 on 13 October 2008. Downloaded from c The patient was too ill to warrant further investigation in final diagnosis. Given that around 8% of patients with normal clinical practise (eg, moribund patients). apparently benign histology on pleural biopsy develop malig- nancy over time,18 all patients with benign disease were Patients were identified by a respiratory trainee (NMR) and followed up (as part of routine clinical practice in our or the referred for TUS with no clinical information on past history, host institution) for a minimum of 12 months to confirm that presenting features or relevant investigations. malignant disease did not develop. For the purposes of this We routinely perform a TUS in all patients presenting as study, ‘‘definitive diagnosis’’ was considered to be the diagnosis above before biopsy, drain insertion or thoracoscopy and, as imparted to the patient and on which basis the patient was such, this study was considered an audit of our current practice treated (see Results). for which local ethics committee approval is not required in our institution. Statistical analysis Details of the statistical analysis are given in the online Ultrasound supplement. Precise details of the ultrasound technique and operators are given in the online supplement. All patients underwent TUS, RESULTS before which the most recent chest radiograph was reviewed. TUS was performed without clinical history and previous three- Patients dimensional (CT/MRI) imaging data. Anonymised video clips From January to September 2005, 52 consecutive patients were and still images of the examination were generated. From these recruited. Their baseline characteristics are summarised in TUS findings an overall diagnosis of malignant or benign pleural table 1. disease was recorded on a reporting proforma (see online supplement). Anonymised TUS data were then reviewed Definitive diagnosis separately by a consultant radiologist experienced in thoracic Malignancy ultrasound (FVG), blind to clinical history, previous investiga- Thirty-three patients of median age 68 years (range 41–89) were tions (including radiology), physical status and appearance of diagnosed with malignant disease and 19 patients of median age the patient. The final results of the blind analysis were recorded 68 years (range 22–88) were diagnosed with benign disease by one of the authors (NRQ). (table 1). The mode of final diagnosis is shown in table 2. In 30/ 33 cases (91%) the definitive diagnosis of malignancy was based TUS diagnosis on histocytological confirmation. In the remaining 3 cases (9%) Morphological criteria established as sensitive and specific to the diagnosis of pleural malignancy was based on follow-up CT malignant pleural disease on CECT were used as the basis of appearances over a period of 6 months in association with a TUS diagnosis. If a patient had any one of the following criteria clinical course (including death in all cases) consistent with malignant disease. on TUS, a diagnosis of malignant disease was recorded: http://thorax.bmj.com/ c Diaphragmatic and parietal pleural nodule or nodules. c Pleural thickening .1 cm. Benign disease c Hepatic metastasis. After initial negative histocytological investigations, all cases of A provisional diagnosis of malignant or benign pleural disease benign disease (19/19) were followed up for a minimum period was recorded on the proforma prior to other investigations and of 12 months. This included patients with positive microbiol- separately by each operator. ogy or ‘‘inflammation’’ on pleural biopsies.