lecture 7

Basic approach to chest X-ray interpretation

Lecture 7 Dr. Kosar kamal ahmed

H.D diagnostic radiology

“ Late better than never “

Intrinsic

•Primary cancersPrimary cancers

•Bronchogenic carcinoma

•Bronchial carcinoid

•Adenoid cystic carcinoma

•MetastasesMetastases (e.g. breast, renal cell and colonic carcinoma, melanoma,

sarcoma)

•LymphomaLymphoma

•Benign tumours (e.g. lipoma, hamartoma, papillomas, endometriomas)

•Granulomatous diseases (e.g. sarcoidosis and tuberculosis)

•Miscellaneous conditions (e.g. aspirated foreign bodies, mucus plugs,

gastric contents, malpositioned endotracheal tubes, bronchial torsion or

rupture, amyloidosis, Wegener's granulomatosis)

Extrinsic

Lobar collapse without endobronchial

obstruction

• Miscellaneous conditions :

• (e.g. passive collapse due to pleural fluid or pneumothorax,

• radiation-induced collapse

•tumour replacement (bronchiolo-alveolar cell carcinoma )

• 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 .

• 1-Relaxation or passive collapse– When air or fluid collects in the pleural space the lung retract toward the hilum.

• 2-cicatrisation collapse– 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– 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– 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.

• The cardinal radiologic features of collapse are :

– Increased opacity + volume loss

• Collapse can be diagnosed by , either :

– Direct signs ( are those due to displacement of interlobar fissures )

– Indirect signs ( are those due to compensatory changes in the adjacent lobes

– A collapsed lobe appears opaque due to retained secretions and decreased

aeriation of the lobe .

1. Displacement of interlobar

fissures

2. Crowding of the pulmonary

vessels and bronchi

3. Volume loss

4. Hilar elevation

5. Small hilum

•Rt. Upper zone opacity , lined by fissure

•Displaced minor fissure superiorly

•Rt. Hilum shift superiorly ( same level with Lt. hilum )

•Shift of minor fissure and upper part of major fissure ( almost parallel )

1. Displacement of interlobar

fissures

2. Crowding of the pulmonary

vessels and bronchi

3. Volume loss

4. Hilar elevation

5. Small hilum

• increased opacity of Rt. Upper zone

( apex )

• Elevation of the horizontal fissure

• Elevated Rt. Hilum


( apex )


• Elevated Rt. Hemi diaphragm with

distorted mediastinal contour


( apex )


• Elevated minor fissure with bulging due to

a central hilar mass causing collapse

• Golden’s S sign


( apex )


• Fissure is not seen because the collapse

is tight and horizontal fissure is parallel to

mediastinum

• 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 ‘veil-like’ 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.

• Other features that aid diagnosis on the frontal view are

– 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)

• 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

• Frontal view

– Veil-like opacity in Lt. hemithorax

– Lt. hilum can not be demarkated

– Mild mediastinal shift and rotation

– Narrowing of carinal angle

• Lateral view

– Shift of entire fissure anteriorly

• 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) .

• Chest radiograph shows

• opacification of the Lt. apex with

silhouette of Lt. mediastinal border – 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

• 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




• 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 .




Summary

• RML collapse can be missed on frontal view and is easy to diagnose in

lateral view

•Radiologic features are variable ranging from

•Subtle increase in density

•Silhouette of Rt. Cardiac border

•Non specific opacity

•Lateral view

•A triangular density with the apex toward the hilum “ degree of collapse

is inversely proportionate with size of the triangle

Findings :

• RML collapse can be missed

on frontal view and is easy to

diagnose in lateral view

•Radiologic features are

variable ranging from

Findings :

• a triangular opacity seen adjacent to

Rt. Cardiac border silhouetting the border

•CT shows a triangular shaped segment

of Rt. Middle lobe ( medial segment ) with

fibrosis and bronciactatic changes

• 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.

• 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 .

• 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

Superior triangle sign

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

• Findings : • Opacified Rt. Hemithorax

• Mediastinal shift toward the

affected side

• Dx. Rt. Lung collapse

• Findings : • Opacified Rt. Hemithorax

• Mediastinal shift toward the

contralateral side

• Dx. Rt. Side huge pleural

effusion

• Findings : • Opacified Lt. Hemithorax

• No considerable mediastinal

shift + air bronchogram sign

• Dx. Lt. lung pneumonia

• Findings : • Opacified Lt. Hemithorax

• Considerable mediastinal shift

to the affected side +

compensatory hypertrophy of

contralateral side + history of

surgery

• Dx. Lt. lung pneumonectomy

Review slide ( causes of opacified hemithorax )

lecture 7

Health & Medicine