Which findings on chest radiography suggest pleural effusions (fluid on the lungs)?

Updated: Dec 28, 2018
  • Author: Kamran Boka, MD, MS; Chief Editor: Guy W Soo Hoo, MD, MPH  more...
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Answer

Effusions of more than 175 mL are usually apparent as blunting of the costophrenic angle on upright posteroanterior chest radiographs. On supine chest radiographs, which are commonly used in the intensive care setting, moderate to large pleural effusions may appear as a homogenous increase in density spread over the lower lung fields. Apparent elevation of the hemidiaphragm, lateral displacement of the dome of the diaphragm, or increased distance between the apparent left hemidiaphragm and the gastric air bubble suggests subpulmonic effusions. (See the images below.)

Isolated, left-sided pleural effusion with visuali Isolated, left-sided pleural effusion with visualized loss of left, lateral costophrenic sulcus. Posteroanterior upright chest radiograph. Image courtesy of Allen R. Thomas, MD.
Bilateral pleural effusions with loss of bilateral Bilateral pleural effusions with loss of bilateral costophrenic sulci (meniscus sign). Anteroposterior, upright chest radiograph. Image courtesy of Allen R. Thomas, MD.

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