1. Atelectasis

2. What does atelectasis mean? Lung collapse with loss of internal air Atelectasis can affect: –a subunit of a lobe (subsegmental) –a lobe –or a whole lung Subsegmental atelectasis is most common

3. Causes of Lobar/Whole Lung Atelectasis Proximal stenosing bronchogenic carcinoma Asthma (mucus plugging) Inhaled foreign body Retention of secretions (e.g. postop) Endotracheal tube inserted too far

4. CXR Features of Lobar/Whole Lung Atelectasis Ipsilateral tracheal displacement Increased density of collapsed lung tissue Ipsilateral mediastinal shift Elevation of the hemidiaphragm Herniation of the opposite lung across the midline

5. Complete left lung collapse

6. Trachea deviated to left Heart shifted to left Opaque (white) hemithorax, caused by non- aerated lung

7. Patterns of Lobar Collapse The left lung has 2 lobes (upper, lower), and the right lung 3 lobes (upper, middle, and lower) The collapse of each lobe has specific appearances on a CXR Examples of each type of lobar collapse now follow A revision of your lung anatomy now might be helpful

8. Surface markings of the lobes The lingula is part of the left upper lobe Note that the lower lobes extend quite high – above the level of the carina

9. Right Upper Lobe Collapse

10. Examples of Lobar Atelectasis There now follows examples of each type of lobar atelectasis. Some are difficult to recognise! For each one, look for volume loss (e.g. ribs closer together), and movement of other structures to occupy the space created by the atelectasis.

11. Right Lower Lobe Collapse

12. The right lung has lost volume and the horizontal fissure is depressed (red arrow)

13. Middle Lobe Collapse

14. The right heart border is blurred. Middle lobe collapse can be very difficult to detect, and a lateral CXR can be helpful if in doubt (next slide)

15. Middle Lobe Collapse Note the wedge shape on the lateral CXR. The horizontal fissure (arrow) is depressed

16. Left Upper Lobe Collapse

17. R

18. Note loss of volume of the left hemithorax and generalised increased density. The lung markings still visible are those of the lower lobe, which expands to fill the space left by the collapsed upper lobe R Left Upper Lobe Collapse

19. Left Lower Lobe Collapse

20. Note loss of left diaphragm contour medially, volume loss of the left hemithorax and the retrocardiac straight line (representing the collapsed lower lobe)

21. Take Home Points The commonest cause of lobar / total lung collapse in adults is lung cancer All patients with lobar or total lung collapse need further assessment to determine the underlying cause The CXR appearances of collapse vary according to where the collapse is