Diagnostic Radiology/Chest Imaging/Chest Signs

Be able to define, identify and state the significance of the following on a radiograph:

  • air bronchogram - indicates a parenchymal process, including non-obstructive atelectasis, as distinguished from pleural or mediastinal processes
  • air crescent sign - indicates a lung cavity, often due to fungal infection
  • deep sulcus sign on a supine radiograph - indicates pneumothorax
  • continuous diaphragm sign - indicates pneumomediastinum
  • ring around the artery sign (around pulmonary artery on lateral chest radiograph) - indicates pneumomediastinum
  • fallen lung sign - indicates a fractured bronchus
  • flat waist sign- indicates left lower lobe collapse
  • gloved finger sign - indicates bronchial impaction, which can be seen in allergic bronchopulmonary aspergillosis
  • Golden S sign - indicates lobar collapse with a central mass, suggesting an obstructing bronchogenic carcinoma in an adult
  • luftsichel sign - indicates upper lobe collapse, potentially due to an obstructing bronchogenic carcinoma in an adult
  • Hampton's hump - indicates a pulmonary infarct
  • silhouette sign - loss of the contour of the heart or diaphragm used to localize a parenchymal process (e.g. a process involving the medial segment of the right middle lobe obscures the right heart border; a lingula process obscures the left heart border; a basilar segmental lower lobe process obscures the diaphragm)
  • cervicothoracic sign - a mediastinal opacity that projects above the clavicles is retrotracheal and posteriorly situated while an opacity effaced along its superior aspect and projecting at or below the clavicles is situated anteriorly
  • tapered margins sign - a lesion in the chest wall, mediastinum or pleura will have smooth tapered borders and obtuse angles with the chest wall or mediastinum while parenchymal lesions usually form acute angles
  • figure 3 sign - abnormal contour of the descending aorta, indicating coarctation of the aorta
  • fat pad sign or sandwich sign - indicates pericardial effusion on lateral chest radiograph
  • scimitar sign - an abnormal pulmonary vein in venolobar syndrome
  • double density sign - contour projecting over the right side of the heart, indicating enlargement of the left atrium
  • hilum overlay sign and hilum convergence sign -used to distinguish a hilar mass from a non-hilar mass

Be able to define, identify and state the significance of the following on a chest CT:

  • CT angiogram sign - enhancing pulmonary vessels against a background of low attenuation material in the lung
  • halo sign - suggesting invasive pulmonary aspergillosis in a leukemic patient
  • split pleura sign - a sign of empyema