Atelectasis

Question 1

What are the direct signs of atelectasis?

Answer 1

• Displacement of the fissures. Vascular crowding.

Mandell, Jacob. Core Radiology (p. 3). Cambridge University Press. Kindle Edition.

Question 2

What are the indirect signs of atelectasis?

Answer 2

• Elevation of the diaphragm.
• Overinflation of adjacent or contralateral lobes.
• Rib crowding on the side with volume loss.
• Hilar displacement.
• Mediastinal shift to the side with volume loss.

Question 3

What are the signs of left lower lobe atelectasis?

Answer 3

• heart slightly rotates and the left hilum is pulled down.
• The flat waist sign describes the flattening of the left heart border as a result of downward shift of hilar structures and resultant cardiac rotation.

Question 4

What are the signs of left upper lobe atelectasis?

Answer 4

• luftsichel (air-sickle in German) is a crescent of air seen on the frontal radiograph, which represents the interface between the aorta and the hyperexpanded superior segment of the left lower lobe.
• On the frontal radiograph: (learningradiology.com)
  
  • There is a hazy area of increased density around the left hilum.
  • There is a leftward shift of the trachea.
  • There may be elevation with “tenting” (peaking) of the left hemidiaphragm.
  • Compensatory overinflation of the lower lobe may cause the superior segment of the left lower lobe to extend to the apex of the thorax on the affected side.
• On the lateral radiograph:
  
  • There is forward displacement of the major fissure and the opacified upper lobe forms a band of increased density running roughly parallel to the sternum.

Question 5

What are the signs of right lower lobe atelectasis?

Answer 5

• Mirror image of left lower lobe collapse appears as a wedge-shaped retrocardiac opacity.
  
  • Mandell, Jacob. Core Radiology (p. 6). Cambridge University Press. Kindle Edition.
• Imaging Findings of Right Lower Lobe Atelectasis (learningradiology.com)
  
  • Increase in density of the affected lung
  • In the case of RLL atelectasis, triangular density at the right lung base that silhouettes the right hemidiaphragm but not the right heart border
  • Displacement of the fissures or the mediastinum towards the atelectasis
  • For RLL atelectasis, the major fissure is displaced downward and medially on the frontal view and downward and posteriorly on the lateral view
  • Elevation of the hemidiaphragm
  • The medial and posterior portions of the right hemidiaphragm may not be visible in RLL atelectasis because they are silhouetted by the collapsed lung above it
  • Overaeration of the upper and middle lobes
  • Downward displacement of the right hilum

Question 6

What are the signs of right middle lobe atelectasis?

Answer 6

• Silhouetting of the right heart border by the collapsed medial segment of the middle lobe may be the only clue. The lateral radiograph shows a wedge-shaped opacity anteriorly.

Question 7

What are the signs of right upper lobe atelectasis?

Answer 7

• Reverse S sign of Golden is seen in right upper lobe collapse caused by an obstructing mass.
  
  • Although the sign describes a reverse S, it is also commonly known as Golden’s S sign.
• The juxtaphrenic peak sign is a peridiaphragmatic triangular opacity caused by diaphragmatic traction from an inferior accessory fissure or an inferior pulmonary ligament.
• Similar to left upper lobe collapse, a right upper lobe collapse should raise concern for an underlying malignancy,

Question 8

What are the signs of round atelectasis?

Answer 8

• Round atelectasis is focal atelectasis with a round morphology that is always associated with an adjacent pleural abnormality (e.g., pleural effusion, pleural thickening or plaque, pleural neoplasm, etc.).
• Round atelectasis is most common in the posterior lower lobes.
• All five of the following findings must be present to diagnose round atelectasis:
  
  • 1) Adjacent pleura must be abnormal.
  • 2) Opacity must be peripheral and in contact with the pleura.
  • 3) Opacity must be round or elliptical.
  • 4) Volume loss must be present in the affected lobe.
  • 5) Pulmonary vessels and bronchi leading into the opacity must be curved — this is the comet tail sign.