6. Lobar collapse without
endobronchial
obstruction
⢠Miscellaneous conditions :
⢠(e.g. passive collapse due to pleural fluid or pneumothorax,
⢠radiation-induced collapse
â˘tumour replacement (bronchiolo-alveolar cell carcinoma )
7. ⢠In the clinical context of a
middle-aged or elderly smoker,
lobar collapse should always be
suspected to be due to a
bronchogenic carcinoma until
proved otherwise
⢠The common causes differ
slightly between adults and
children.
⢠In children the frequent causes
of intrinsic obstruction are
tumours and mucus plugs .
8. ⢠1-Relaxation or passive collapse
â When air or fluid collects in the pleural space the lung retract toward the hilum.
⢠2-cicatrisation collapse
â The normal lung expantion is maintained by abalance between an outward force by the
chest wall and an opposite force by the elasticity of the lung, when the lung become stiff,
lung compliance decrease and the lung volume decrease e.g in pulmonary fibrosis.
⢠3-Adhesive collapse
â The surface tension of alveoli are decreased by the surfactant, if the surfactant is
disturbed e.g in ARDS the alveoli will collapse although the central airway remains
patent.
⢠4- Resorption collapse
â In chronic bronchial obstruction there will be subsequent resorption of intra alveolar
secretion and exudate and may result in complete collapse e.g seen in CA bronchus.
9. ⢠The cardinal radiologic features of collapse are :
â Increased opacity + volume loss
⢠Collapse can be diagnosed by , either :
â Direct signs ( are those due to displacement of interlobar fissures )
â Indirect signs ( are those due to compensatory changes in the adjacent
lobes
â A collapsed lobe appears opaque due to retained secretions and decreased
aeriation of the lobe .
10. 1. Displacement of interlobar
fissures
2. Crowding of the pulmonary
vessels and bronchi
3. Volume loss
4. Hilar elevation
5. Small hilum
11. â˘Rt. Upper zone opacity , lined by fissure
â˘Displaced minor fissure superiorly
â˘Rt. Hilum shift superiorly ( same level with Lt. hilum )
â˘Shift of minor fissure and upper part of major fissure ( almost parallel )
12. 1. Displacement of interlobar
fissures
2. Crowding of the pulmonary
vessels and bronchi
3. Volume loss
4. Hilar elevation
5. Small hilum
13. ⢠increased opacity of Rt. Upper zone
( apex )
⢠Elevation of the horizontal fissure
⢠Elevated Rt. Hilum
14. ⢠increased opacity of Rt. Upper zone
( apex )
⢠Elevated Rt. Hilum
⢠Elevated Rt. Hemi diaphragm with
distorted mediastinal contour
15. ⢠increased opacity of Rt. Upper zone
( apex )
⢠Elevated Rt. Hilum
⢠Elevated minor fissure with bulging due to
a central hilar mass causing collapse
⢠Goldenâs S sign
16. ⢠increased opacity of Rt. Upper zone
( apex )
⢠Elevated Rt. Hilum
⢠Fissure is not seen because the collapse
is tight and horizontal fissure is parallel to
mediastinum
17.
18. ⢠The cardinal features of LUL collapse are fundamentally different from RUL
collapse as there is very rarely a horizontal fissure on the left.
⢠Consequently, the main direction of volume loss is anteriorly and medially rather
than superiorly, and the entire oblique fissure is displaced in that direction
parallel to the chest wall on the lateral view.
⢠On the frontal view the signs may be variable depending on the degree of
collapse, but there is a âveil-likeâ increased density of the whole of the affected
hemithorax in most cases.
⢠The difference in transradiancy may be relatively subtle and therefore overlooked
by the unwary.
19. ⢠Other features that aid diagnosis on the frontal view are
â loss of the normal silhouette of structures adjacent to the collapse, such as
the left heart border, mediastinum, and aortic arch and the variability of
obscuring of these structures vary with the degree of the collapse.
⢠In severe cases the apical segment of the left lower lobe is hyperexpanded
superiorly adjacent to the aortic arch and somewhat paradoxically the aortic
knuckle outline is therefore visible in more severe cases as it is adjacent to
aerated lung (The Luftsichel sign)
20. ⢠On the lateral view the anterior outline of the ascending thoracic aorta can be
seen with unusual clarity and this is due to compensatory hyperinflation of the
right upper lobe across the midline and rotation of the mediastinum so the
anterior aspect of the aorta is outlined by aerated lung tangential to the X-ray
beam
⢠On the frontal radiograph the left main bronchus is reorientated and has a more
horizontal course than usual.
⢠The superior displacement of this structure results in angulation between the left
main bronchus and the left lower lobe bronchus
21. ⢠Frontal view
â Veil-like opacity in Lt. hemithorax
â Lt. hilum can not be demarkated
â Mild mediastinal shift and rotation
â Narrowing of carinal angle
⢠Lateral view
â Shift of entire fissure anteriorly
22. ⢠PA chest radiograph shows :
⢠A crescentic lucency adjacent to the aortic
arch , representing hyperaeration of the
superior segment of the left lower lobe, which
is positioned between the aortic arch
medially and the collapsed left upper lobe
laterally.
⢠There is hazy opacification of the left lung
(sparing the apex and costophrenic angle) .
23. ⢠Chest radiograph shows
⢠opacification of the Lt. apex with
silhouette of Lt. mediastinal border
â The changes can be due to collapse or
mass
⢠CT shows
⢠a triangular mass adjacent to aortic
arch which does not reach the Lt.
cardiac border because lingula is
spared from collapse
24. ⢠What do you think ?
⢠Is there abnormality ?
⢠Would you send for a lateral view ?
⢠Silhouette of Lt. cardiac border
⢠A pattern like middle lobe collapse
seen in lateral view
⢠Lingula collapse
25. ⢠What do you think ?
⢠Is there abnormality ?
⢠Would you send for a lateral view ?
⢠The features of right middle lobe collapse may be extremely subtle on the frontal
view and consequently easy to overlook.
⢠The collapsed lobe lies adjacent to the right heart border and there is loss of the
silhouette of this structure to a variable degree
⢠the triangular density of the collapsed right middle lobe is relatively easy to
identify on the lateral view, with approximation of the minor and inferior portion of
the major fissure, the apex of the triangle being at the hilum
⢠In increasingly severe collapse the triangular shape is less marked as the fissures
become almost parallel with only a thin wedge of density separating them .
26. ⢠What do you think ?
⢠Is there abnormality ?
⢠Would you send for a lateral view ?
Summary
⢠RML collapse can be missed on frontal view and is easy to diagnose in
lateral view
â˘Radiologic features are variable ranging from
â˘Subtle increase in density
â˘Silhouette of Rt. Cardiac border
â˘Non specific opacity
â˘Lateral view
â˘A triangular density with the apex toward the hilum â degree of collapse
is inversely proportionate with size of the triangle
27. Findings :
⢠RML collapse can be missed
on frontal view and is easy to
diagnose in lateral view
â˘Radiologic features are
variable ranging from
28. Findings :
⢠a triangular opacity seen adjacent to
Rt. Cardiac border silhouetting the border
â˘CT shows a triangular shaped segment
of Rt. Middle lobe ( medial segment ) with
fibrosis and bronciactatic changes
29. ⢠The features of right and left lower lobe collapse
are very similar .
⢠In collapse of the lower lobes, the oblique fissure
is displaced posteriorly and medially, and the
collapsed lobe lies in the posteromedial portion of
the chest
⢠On the frontal radiograph, the collapsed lower
lobes usually form a triangular density behind the
heart .
⢠The medial portion of the hemidiaphragm may be
obscured as it is no longer outlined by aerated lung
⢠but if the inferior pulmonary ligament is incomplete
and does not attach to the diaphragm, the medial
contour of the diaphragm may still be visualized.
30. ⢠On the lateral radiograph, a posterior
portion of the hemidiaphragm may not
be seen .
⢠The vertebral column appears
progressively denser inferiorly in
lower lobe collapse .
31. ⢠The radiologic findings of collapse differs according to the degree ( severity ) of the
collapse
⢠Some mediastinal signs can help in Dx of collapse in cases with overlap
appearances :
⢠1. superior triangle sign
⢠2. flat waist sign
33. Flat waist sign
⢠Leftward displacement and rotation of the
heart in left lower lobe collapse results in
flattening of the contours of the aortic knob
and adjacent main pulmonary artery ,
termed the flat waist sign
34.
35. ⢠Findings :
⢠Opacified Rt. Hemithorax
⢠Mediastinal shift toward the
affected side
⢠Dx. Rt. Lung collapse
36. ⢠Findings :
⢠Opacified Rt. Hemithorax
⢠Mediastinal shift toward the
contralateral side
⢠Dx. Rt. Side huge pleural
effusion
38. ⢠Findings :
⢠Opacified Lt. Hemithorax
⢠Considerable mediastinal shift
to the affected side +
compensatory hypertrophy of
contralateral side + history of
surgery
⢠Dx. Lt. lung pneumonectomy