Official reprint from UpToDate®
www.uptodate.com ©2018 UpToDate, Inc. and/or its affiliates. All Rights Reserved.

Imaging of pleural effusions in adults

Paul Stark, MD
Section Editors
Talmadge E King, Jr, MD
Nestor L Muller, MD, PhD
V Courtney Broaddus, MD
Deputy Editors
Geraldine Finlay, MD
Susanna I Lee, MD, PhD


Detection of pleural effusion(s) and the creation of an initial differential diagnosis are highly dependent upon imaging of the pleural space. Conventional chest radiography and computed tomography (CT) scanning are the primary imaging modalities that are used for evaluation of all types of pleural disease, but ultrasound and magnetic resonance imaging (MRI) have a role in selected clinical circumstances.

The imaging of pleural effusions will be presented here. Imaging of pleural plaques, thickening, tumors, and pneumothorax are discussed separately. (See "Imaging of pleural plaques, thickening, and tumors" and "Imaging of pneumothorax".)


The term pleura is generally meant to encompass the parietal pleura (lining the inner surface of the chest wall, including the diaphragmatic pleura and the cervical pleura also called dome of pleura or pleural cupola that covers the lung apex and extends into the cervical region), the visceral pleura (lining the outer surface of the lung), and the intervening pleural space. Both visceral and parietal pleural surfaces consist of a mesothelial layer and three to seven connective tissue layers, but the visceral pleura is thicker than the parietal pleura. Together, the visceral and parietal pleural layers and the lubricating liquid in the interposed pleural space have a combined thickness of 0.2 to 0.4 mm, while the width of the pleural space is 10 to 20 micrometers. (See "Mechanisms of pleural liquid turnover in the normal state".)

Normal pleural anatomy can be displayed by computed tomography (CT) scanning [1]. A 1 to 2 mm thick line of soft-tissue attenuation can be seen at the point of contact between the lung and the chest wall, corresponding to the visceral and parietal pleura and the minimal amount of lubricating pleural liquid (image 1).

Extrapleural fat and the endothoracic fascia, each with a thickness of 0.25 mm, are visible between the pleural line and the ribs (or the subcostal and innermost intercostal muscles). The apical part of the endothoracic fascia is thickened and is called Sibson's fascia. Outside this fascia is a space filled with areolar tissue, called Semb's space. The anterior and posterior junction lines are well outlined by lung and contain four layers of pleura: two visceral and two parietal components (image 2A-B). The interlobar fissures and most accessory fissures in the lungs are formed by two layers of visceral pleura, with the exception of the azygos vein fissure, which contains four layers of pleura, ie, two visceral and two parietal layers of pleura.

To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information on subscription options, click below on the option that best describes you:

Subscribers log in here

Literature review current through: Dec 2017. | This topic last updated: Feb 21, 2017.
The content on the UpToDate website is not intended nor recommended as a substitute for medical advice, diagnosis, or treatment. Always seek the advice of your own physician or other qualified health care professional regarding any medical questions or conditions. The use of this website is governed by the UpToDate Terms of Use ©2018 UpToDate, Inc.
  1. Im JG, Webb WR, Rosen A, Gamsu G. Costal pleura: appearances at high-resolution CT. Radiology 1989; 171:125.
  2. Raasch BN, Carsky EW, Lane EJ, et al. Pleural effusion: explanation of some typical appearances. AJR Am J Roentgenol 1982; 139:899.
  3. Stark P. The pleura. In: Radiology. Diagnosis Imaging, Intervention, Taveras, Ferrucci (Eds), Lippincott, Philadelphia 2000. p.1-29.
  4. Moskowitz H, Platt RT, Schachar R, Mellins H. Roentgen visualization of minute pleural effusion. An experimental study to determine the minimum amount of pleural fluid visible on a radiograph. Radiology 1973; 109:33.
  5. Woodring JH. Recognition of pleural effusion on supine radiographs: how much fluid is required? AJR Am J Roentgenol 1984; 142:59.
  6. Ruskin JA, Gurney JW, Thorsen MK, Goodman LR. Detection of pleural effusions on supine chest radiographs. AJR Am J Roentgenol 1987; 148:681.
  7. Fleischner, FG. Atypical arrangement of free pleural effusion. Radiol Clin North Am 1963; 1:347.
  8. Radiologic Pathology, 4th ed, Armed Forces Institute of Pathology, Washington DC 2005. Vol 1, p.214.
  10. Stark P, Leung A. Effects of lobar atelectasis on the distribution of pleural effusion and pneumothorax. J Thorac Imaging 1996; 11:145.
  11. Catalano O. The incomplete border sign. Radiology 2002; 225:129.
  12. Völk M, Strotzer M, Feuerbach S. Case of the month. Intrapulmonary or extrapulmonary? Br J Radiol 2000; 73:451.
  13. Parker MS, Chasen MH, Paul N. Radiologic signs in thoracic imaging: case-based review and self-assessment module. AJR Am J Roentgenol 2009; 192:S34.
  14. Kraus GJ. The split pleura sign. Radiology 2007; 243:297.
  15. Evans AL, Gleeson FV. Radiology in pleural disease: state of the art. Respirology 2004; 9:300.
  16. Stark DD, Federle MP, Goodman PC, et al. Differentiating lung abscess and empyema: radiography and computed tomography. AJR Am J Roentgenol 1983; 141:163.
  17. Westcott JL, Volpe JP. Peripheral bronchopleural fistula: CT evaluation in 20 patients with pneumonia, empyema, or postoperative air leak. Radiology 1995; 196:175.
  18. Sarkar P, Patel N, Chusid J, et al. The role of computed tomography bronchography in the management of bronchopleural fistulas. J Thorac Imaging 2010; 25:W10.
  19. Seo H, Kim TJ, Jin KN, Lee KW. Multi-detector row computed tomographic evaluation of bronchopleural fistula: correlation with clinical, bronchoscopic, and surgical findings. J Comput Assist Tomogr 2010; 34:13.
  20. McNeary M, Stark P. Radiographic findings in ovarian hyperstimulation syndrome. J Thorac Imaging 2002; 17:230.
  21. Moore CL, Copel JA. Point-of-care ultrasonography. N Engl J Med 2011; 364:749.
  22. Gamsu G, Sostman D. Magnetic resonance imaging of the thorax. Am Rev Respir Dis 1989; 139:254.
  23. Zerhouni EA. MR imaging in chest disease: Present and future applications Syllabus: A categorical course in chest radiology. RSNA 1992; :25.
  24. Porcel JM, Hernández P, Martínez-Alonso M, et al. Accuracy of fluorodeoxyglucose-PET imaging for differentiating benign from malignant pleural effusions: a meta-analysis. Chest 2015; 147:502.
  25. Müller NL. Imaging of the pleura. Radiology 1993; 186:297.
  26. Kutty CP, Varkey B. "Contarini's condition:" bilateral pleural effusions with markedly different characteristics. Chest 1978; 74:679.
  27. Maher GG, Berger HW. Massive pleural effusion: malignant and nonmalignant causes in 46 patients. Am Rev Respir Dis 1972; 105:458.
  28. Light RW. Pleural Diseases, 5th ed, Lippincott, Williams, and Wilkins, Philadelphia 2013.
  29. Hulnick DH, Naidich DP, McCauley DI. Pleural tuberculosis evaluated by computed tomography. Radiology 1983; 149:759.
  30. Kearney SE, Davies CW, Davies RJ, Gleeson FV. Computed tomography and ultrasound in parapneumonic effusions and empyema. Clin Radiol 2000; 55:542.
  31. Friedman PJ, Hellekant CA. Radiologic recognition of bronchopleural fistula. Radiology 1977; 124:289.
  32. Chernow B, Sahn SA. Carcinomatous involvement of the pleura: an analysis of 96 patients. Am J Med 1977; 63:695.
  33. Fentiman IS, Millis R, Sexton S, Hayward JL. Pleural effusion in breast cancer: a review of 105 cases. Cancer 1981; 47:2087.
  34. Wolverson MK, Crepps LF, Sundaram M, et al. Hyperdensity of recent hemorrhage at body computed tomography: incidence and morphologic variation. Radiology 1983; 148:779.
  35. Romero M, Bächler P. Pseudo-hemothorax at computed tomography due to residual contrast media. Clin Imaging 2014; 38:333.
  36. Davis SD, Henschke CI, Yankelevitz DF, et al. MR imaging of pleural effusions. J Comput Assist Tomogr 1990; 14:192.
  37. Roy PH, Carr DT, Payne WS. The problem of chylothorax. Mayo Clin Proc 1967; 42:457.
  38. Yu DX, Ma XX, Wang Q, et al. Morphological changes of the thoracic duct and accessory lymphatic channels in patients with chylothorax: detection with unenhanced magnetic resonance imaging. Eur Radiol 2013; 23:702.