1) Lobar collapse refers to the collapse of an entire lobe of the lung, which can be caused by obstruction of the supplying bronchus. 2) Signs of lobar collapse include shift of fissures, crowding of pulmonary vessels, hemithorax elevation, mediastinal shift, and compensatory hyperinflation of normal lobes. 3) Collapse of different lung lobes shows characteristic radiographic findings, such as Golden's S sign for right upper lobe collapse and the Luftsichel sign for left upper lobe collapse.

1. LOBAR COLLAPSE OF
LUNGS
- Dr. Pradeep Patil
Dr. D. Y. Patil Medical College Hospital, Kolhapur
Dept. of Radiodiagnosis

2. Lobes of Lungs

3. R

5. lobar anatomy- Left lung- 2 lobes

7. LOBAR COLLAPSE

8. LOBAR COLLAPSE
• Lobar collapse refers to collapse of an entire lobe of the lung.
• it is a sub type of atelectasis.
• Individual lobes of the lung may collapse due to obstruction of the
supplying bronchus.

9. Causes of lobar collapse
extrinsic
• compression by adjacent mass
luminal
• aspirated foreign material
• mucous plugging
• endobronchial mass
• misplaced endotracheal tube
mural
• bronchogenic carcinoma

10. Signs of Lobar Collapse
• Lobar
• Shift of fissure
• Crowding of pulmonary vessels
(increased opacity)
• Extra lobar
• I/L Hemi diaphragm elevation
• Mediastinal shift
towards side of collapse
• Hilar displacement towards
the collapse
• Compensatory hyperinflation of
normal lobes
• Rib approximation
(crowding of ipsilateral ribs)
• Shift of other structures

11. Right upper lobe collapse
RUL collapse
Horizontal fissure displaced upward
Hilum is elevated
Tracheal deviation to right
Compensatory hyperinflation of
right middle and lower lobes may be seen

12. Right upper lobe collapse
• On the lateral projection it is harder to identify as the soft tissues of the shoulders usually
obscure the upper zones, and the collapse is mostly medial.
• Elevation of the horizontal fissure and upper part of the oblique fissure may be visible
• Both fissures concave superiorly

13. Right upper lobe collapse

14. Golden’s S sign
The sign refers to the S shape ( or more accurately , reverse S on the right)
of the fissure due to the combination of collapse and mass centrally resulting
in a focal convexity with a concave outline.

15. Golden’s
S sign

16. Juxtaphrenic peak sign
• The juxtaphrenic peak sign,
which occurs in upper lobe
atelectasis, describes the
triangular opacity projecting
superiorly at the medial half of
the diaphragm.

17. D/D
• The differential diagnosis of collapse of the right upper lobe
includes:
1. consolidation of the right upper lobe
2. a mass in the medial aspect of the right upper lobe
3. a mass in on the right side of the superior mediastinum

18. Right Middle Lobe Collapse
• Horizontal fissure and oblique fissure move towards one another
• Obscuration of right heart border
• Volume of this lobe is small so indirect signs rarely present.

19. Right Middle Lobe collapse

20. Silhouette Sign
• If two soft tissue densities lie in apposition, then they will not be
visible separately
• If they are separated by air, the boundaries of both will be seen

21.  Uses of Silhouette
1. Localisation without a lateral view
2. Loss of clarity of a structure suggests there is
adjacent soft tissue shadowing even when the
abnormality itself is not clearly visualised. This is
particularly valuable in some cases of lobar
collapse.

22. Right Middle lobe Collapse
1: Right horizontal and oblique fissure move towards each other often
subtle
2: Blur the normally sharp right-heart border (silhouette sign)

23. Posteroanterior (PA) (left) and lateral chest (right) radiographs.
A right middle lobe collapse obliterates the right heart border
on the PA image and projects as a wedge-shaped opacity on
the lateral view.

24. D/D
1. Frontal projection
On frontal (PA or AP) projection, right middle lobe collapse should be distinguished
from:
•consolidation of the right middle lobe
•pectus excavatum: downward sloping ribs and shift of the heart away from the right
are clues. Lateral projections makes the distinction easy.
2. Lateral projection
On the lateral projection, right middle lobe collapse should be distinguished from:
•fluid within the oblique fissure (pseudotumour): horizontal fissure should be visible
as separate to the opacity 2
•fat within the oblique fissure
•consolidation of the right middle lobe

25. Right Lower lobe collapse
• Depression of horizontal fissure
• Increase opacity of collapse lower lobe
• In case of complete collapse of lower lobe it may be so small that it merges with mediastinum
and produce a thin wedge shape shadow.
• Mediastinal parts and adjacent diaphragm obscured
• Hila depressed
• Diaphragm elevation is not usual

26. Right Lower lobe collapse
Posterior and medial collapse
Obliteration of the right hemi diaphragm
Heart border clearly seen
Transverse fissure pulled inferiorly

27. The lateral view is usually definitive-
there will be postero-inferior movement
of the oblique fissure whilst
maintaining the same slope
The lower lobes collapse downward
medially toward the spine and
posteriorly

28. Superior Triangle Sign
• triangular density to the right of mediastium seen in right lower lobe collapse due to
displacement of anterior junctional stuctures

29. right lower lobe collapse that results in volume loss,
obliteration of the right side of the diaphragm, and a
posterior opacity.

30. D/D
The characteristic shape associated with volume loss usually does not
allow for any significant differential diagnosis. As always one should
consider:
• consolidation (of the medial basal segment of the right lower lobe)
• a pulmonary or posterior mediastinal mass
• The location is also a favourite for pulmonary sequestration.

31. Left Upper Lobe Collapse
• veil like opacity
• aortic knuckle, left hilum, and left-heart border initially ill
defined but may progress to become sharp
• almost vertical oblique fissure

32. • Loss of volume on left side
• I/L shift of trachea and
mediastinum
• Compensatory hyperinflation
of left lung
• Raised left hemidiaphragm
( compare with right with
tenting)
• Haziness over the aortic
knuckle
( silhouette sign)

33. • Oblique fissure
displaced anteriorly
• Opacification anterior to
the oblique fissure
• Anterior displacement
of entire oblique fissure
• Aortic knuckle obscured
LEFT UPPER LOBE COLLAPSE
LATERAL VIEW

34. • With increasing collapse upper
lobe retracts posteriorly and
loses contact with anterior chest
wall.
• The space between the
collapsed lung and sternum is
occupied by either hyperinflated
left lower lobe or herniated
right upper lobe.
• When complete collapse occurs
LUL lose contact with chest wall
and diaphragm and retract
medially against the
mediastinum

36. Luftsichel sign
• The word“Luftsichel” in
German means“air crescent”
• This sign is seen in severe left
upper lobe collapse.
• Due to the lack of a minor
fissure on the left side, upper
lobe collapse causes vertical
positioning and anterior and
medial displacement of the
major fissure.
• The superior segment of the left
lower lobe migrates superior
and anteriorly between the arch
of the aorta and the atelectatic
lobe.
• The crescent-shaped
radiolucency around the aortic
arch is called the Luftsichel sign

37. Left Upper Lobe Collapse
‘Luftsichel’

38. Left lower lobe collapse
• Posterior and medial collapse
• triangular opacity – sail sign
• hemidiaphragm may be obscured

39. • The PA view will show a triangular
area of increased opacity behind
the left heart shadow.
• There may be loss of visualisation
of the left hemi-diaphragm
behind the heart
• The lower lobes collapse
• downward
• medially toward the spine and
• posteriorly

40. •In the lateral view a
triangular opacity will be
seen at the base of the
lung with a sharply
defined anterior margin
formed by the oblique
fissure

41. Left Lower lobe collapse

42. D/D
• The characteristic shape associated with volume loss usually does not
allow for any significant differential diagnosis. As always one should
consider:
1. consolidation (of the medial basal segment of the right lower lobe)
2. a pulmonary or posterior mediastinal mass

43. Summary Right
•Right Upper lobe
•Right middle lobe
•Right Lower Lobe

44. Summary Left
•Left upper lobe
•Left lower lobe

45. Thank You