1
Q
What are the direct signs of atelectasis?
A
- Displacement of the fissures. Vascular crowding.
Mandell, Jacob. Core Radiology (p. 3). Cambridge University Press. Kindle Edition.
2
Q
What are the indirect signs of atelectasis?
A
- 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.
3
Q
What are the signs of left lower lobe atelectasis?
A
- 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.
4
Q
What are the signs of left upper lobe atelectasis?
A
- 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.
5
Q
What are the signs of right lower lobe atelectasis?
A
- 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
6
Q
What are the signs of right middle lobe atelectasis?
A
- 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.
7
Q
What are the signs of right upper lobe atelectasis?
A
- 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,
8
Q
What are the signs of round atelectasis?
A
- 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.
