Which findings on chest radiographs suggest pneumothorax?

Updated: Apr 28, 2020
  • Author: Brian J Daley, MD, MBA, FACS, FCCP, CNSC; Chief Editor: Mary C Mancini, MD, PhD, MMM  more...
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Answer

Finding of pneumothorax on chest radiographs may include the following:

  • A linear shadow of visceral pleura with lack of lung markings peripheral to the shadow may be observed, indicating collapsed lung
  • An ipsilateral lung edge may be seen parallel to the chest wall
  • In supine patients, deep sulcus sign (very dark and deep costophrenic angle) with radiolucency along costophrenic sulcus may help to identify occult pneumothorax; the anterior costophrenic recess becomes the highest point in the hemithorax, resulting in an unusually sharp definition of the anterior diaphragmatic surface due to gas collection and a depressed costophrenic angle
  • Small pleural effusions commonly are present and increase in size if the pneumothorax does not reexpand
  • Mediastinal shift toward the contralateral lung may also be apparent
  • Airway or parenchymal abnormalities in the contralateral lung suggest causes of secondary pneumothorax; evaluation of the parenchyma in the collapsed lung is less reliable

Although expiratory images are thought to better depict subtle pneumothoraces (the volume of the pneumothorax is constant and hence proportionally higher on expiratory images), a randomized controlled trial revealed no difference in the ability of radiologists to detect pneumothoraces on inspiratory and expiratory images after procedures with the potential to cause pneumothoraces. (See the images below.)

Radiograph of a patient with a small spontaneous p Radiograph of a patient with a small spontaneous primary pneumothorax
Close radiographic view of patient with a small sp Close radiographic view of patient with a small spontaneous primary pneumothorax (same patient as from the previous image).
Expiratory radiograph of a patient with a small sp Expiratory radiograph of a patient with a small spontaneous primary pneumothorax (same patient as in the previous images).
Radiograph of a patient with spontaneous primary p Radiograph of a patient with spontaneous primary pneumothorax due to a left upper lobe bleb.
Close radiographic view of a patient with spontane Close radiographic view of a patient with spontaneous primary pneumothorax due to a left upper lobe bleb (same patient as in the previous image).

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