Pneumothorax

The chapter titled pneumothorax discusses the radiographic and computed tomography (CT) manifestations of this entity. Pneumothorax may be divided clinically into three types: primary spontaneous, secondary spontaneous, and traumatic. Primary spontaneous pneumothorax is most common in tall, young male smokers and occurs in the absence of visible lung pathology. It is usually secondary to rupture of a small apical bleb or bulla. Secondary spontaneous pneumothorax occurs in patients with underlying lung pathology such as cavitary or cystic metastases, cystic lung disease, interstitial lung disease, and certain infections such as Pneumocystis jiroveci or Staphylococcus aureus pneumonia. Pneumothorax manifests on upright radiography as an apicolateral thin pleural line with no peripheral visible lung markings. On supine radiography, pneumothorax is more difficult to detect but may manifest with increased basal lucency, sharp delineation of adjacent structures such as mediastinal fat and hemidiaphragm, and the deep sulcus sign. Although tension pneumothorax is a clinical diagnosis, there are several radiographic signs that suggest the diagnosis including contralateral mediastinal shift and ipsilateral hemidiaphragm depression or inversion.