Atelectasis
From Ask Dr Wiki
Contents |
Discussion
Types of atelectasis
Lobar collaspe
Right upper lobe collapse
Discussion
- Collapsed RUL shifts medially and superiorly, resulting in elevation of the right hilum and the minor fissure.
- Minor fissure in RUL collapse is usually convex at its superior aspect, but it may appear concave because of an underlying mass lesion.. This is called the S sign of Golden .
- Tenting of the diaphragmatic pleura, called juxtaphrenic peak sign, is another helpful sign of RUL atelectasis
Images
Patient #1
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Right middle lobe collapse
Discussion
- RML collapse obscures the right heart border on a PA image.
- Lateral view shows a triangular opacity overlying the heart because the major fissure shifts upward and the minor fissure shift downward.
Images
Right lower lobe collapse
Discussion
- Collapsed RLL shifts posteriorly and inferiorly resulting in a triangular opacity that obscures the RLL pulmonary artery.
- The major fissure, normally not visible on a PA radiograph, is evident with RLL collapse.
- Superior mediastinal structure shifts to the right, causing a superior triangle sign.
- Laterally, the collapsed RLL obliterates the posterior one third of the right hemidiaphragm and projects as an opacity over the normally lucent area.
Images
Patient #1
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Left upper lobe collapse
Discussion
- Atelectatic LUL shifts anteriorly and superiorly.
- In one half of the cases, a hyperexpanded superior segment of the LLL is positioned between the atelectatic upper lobe and the aortic arch. This gives the appearance of a crescent of the aerated lung, called the luftsichel sign .
- On PA views, an atelectatic LUL produces a faint opacity in the left upper hemithorax, obliterating the left heart border.
- On lateral views, the major fissure is displaced anteriorly behind the sternum.
Images
Left lower lobe collapse
Discussion
- On frontal views, increased retrocardiac opacity obliterates the LLL pulmonary artery and the left hemidiaphragm. The hilar structures shift downward, and the rotation of the heart produces flattening of the cardiac waist, which is known as the flat-waist sign .
- The superior mediastinum may shift and obliterate the aortic arch; this is the top of the aortic-knob sign.
- On the lateral radiographs, an opacity silhouettes the posterior third of the left diaphragm, and an opacity is projected over the normally lucent area.
Images
External Links
References
Sharma, Sat. E-medicine radiology article
