Chest x ray-fundamentals

Dr. Emad Efat
MB BCh, MSc
Faculty of Medicine, Menoufia University
November 2020
Chest X-Ray Fundamentals

Chest X-ray - Tutorials
1. Chest X-ray - Systematic approach
2. Chest X-ray - Quality
3. Chest X-ray - Anatomy
4. Chest X-ray - Abnormalities
5. Chest X-ray - Tubes

Chest X-ray - Systematic approach
Anatomical structures to check:
1. Trachea and bronchi
2. Hilar structures
3. Lung zones
4. Pleura
5. Lung lobes and fissures
6. Costophrenic angles
7. Diaphragm
8. Heart
9. Mediastinum
10. Soft tissues
11. Bones
12. Below diaphragm and hidden areas

Systematic approach
Anatomical structures to check:

Systematic approach - Patient and image data
 Check the patient's identity
 Note the image date and time
 Note the image projection: Check if a posterior anterior
(PA) or anterior posterior (AP) projection was used, and
note if the patient was standing, sitting or supine? Was
the mobile X-ray machine used?
 The image annotations are often useful:
This is a mobile chest X-ray
taken with the patient supine,
at 11.25 am in the resuscitation
room. The patient's name, ID
number and date of birth are
annotated. Note the side
marker is correct.

Systematic approach - projection
1. P-A view
2. A-P view : for
Ambulatory limit
3. Lateral ( Lt/Rt )
4. A-P supine
5. Lateral decubitus
(Lt/Rt)
6. Lordotic : for
Apical lesion
7. Oblique (Rt/Lt;
post/anterior)

Systematic approach - Image quality
 Assess the image quality: The chest X-ray should be
checked for rotation, inspiration and penetration
(Mnemonic-RIP-Rest In Peace ).
 Comment on the presence of medical artifacts
 Can the clinical question still be answered?

Systematic approach - The obvious abnormality
 It is often appropriate to start by describing the most
striking abnormality. However, once you have done this,
it is vital to continue checking the rest of the image.
Remember that the most obvious abnormality may not
be the most clinically important.
The elephant in the
image!
If there is an elephant
in the image, don't
ignore it! Describe it
in detail and then use
your system to
continue examining the
image.

Systematic approach - Describing abnormalities
 'Shadowing', 'Opacification', 'increased density',
'increased whiteness' are all acceptable terms
 'Lesion descriptors' may lead you towards a diagnosis
 Be descriptive rather than jumping to a diagnosis
'Lesion descriptors'
6. Position Anterior/
Posterior/Lung zone etc.
7. Shape Round/ Crescentic/etc.
8. Edge Smooth/
Irregular/Spiculated
9. Pattern Nodular/
Reticular(netlike)
10.Density Air/ Fat/Soft tissue/
Calcium/Metal
1. Tissue involved Lung,
heart, aorta, bone etc.
2. Size Large/ Small/Varied
3. Side Right/ Left
Unilateral/ Bilateral
4. Number Single/ Multiple
5. Distribution Focal/
Widespread

Systematic approach - Describing abnormalities
'Shadows, opacities, densities'
 Tissue involved: Lung
 Size: Small (>2 cm)
 Side: Bilateral
 Number: Multiple
 Distribution: Widespread
 Position: Mainly middle
to lower zones
 Shape: Round
 Edge: Irregular
 Pattern: Nodular
 Density: Soft tissue
 Diagnosis:
 Description helps with diagnosis. Once you have put all the above terms
together, there can only be one diagnosis.
 Metastatic disease

Systematic approach - Locating abnormalities
 Consider its anterior-posterior position.
 A lateral view may help, but 3D location may also be
possible on a posterior-anterior (PA) view if you have a
knowledge of chest X-ray anatomy and an understanding
of the 'silhouette' sign.
The 'silhouette' sign:
The silhouette sign is a misnomer !
 It should be called the 'loss of silhouette' sign.
 Normal adjacent anatomical structures of differing
densities form a crisp 'silhouette,' or contour.
 Loss of a specific contour can help determine
the position of a disease process.

The 'silhouette' sign: Loss of contour of :
1 - Left heart border Lingula disease
2 - Hemidiaphragm Lower lobe lung disease
3 - Paratracheal stripe Paratracheal disease
4 - Chest wall Lung, pleural or rib disease

The 'silhouette' sign: Loss of contour of :
5 - Aortic knuckle Anterior mediastinal or left upper lobe disease
6 - Paraspinal line Posterior thorax disease
7 - Right heart border Middle lobe disease

Systematic approach - Review areas
 After a systematic look at the whole chest X-ray, it is worth
re-checking hidden areas that may conceal important
pathology.
Hidden areas:
• Apical zones
• Hilar zones
• Retrocardial zone
• Zone below the
dome of diaphragm

Systematic approach - Interpretation
Whatever the findings are,
they should only be
interpreted in view of the
clinical setting.
Remember to treat the
patient - not the X-ray!
Occasionally there will be
an unexpected finding
(Incidental Finding), which
may need to be considered
with caution, especially if
equivocal or if it does not
fit the clinical scenario.
Posteroanterior (PA) chest
radiograph shows an incidental
finding of a solitary pulmonary
nodule adjacent to the left hilum.

Chest X-ray quality - Inclusion
Check the image for: Inclusion, Projection, Rotation,
Inspiration, Penetration and Artifact.
Check to see if a poor quality X-ray demonstrates a life
threatening abnormality before dismissing it.
Check to see if the clinical question still be answered?
Inclusion:
A chest X-ray
should include
the entire thoracic
cage ( first ribs,
Costophrenic
angles, Lateral
edges of ribs ).

Chest X-ray quality - Projection
AP projection :
AP projection image is of
lower quality than PA image.
The scapulae are not retracted
laterally and they remain
projected over each lung.
Heart size is exaggerated

Chest X-ray quality - Rotation
Rotation:
 The spinous processes should lie
half way between the medial
ends of the clavicles
 Rotation affects heart size &
shape, aortic tortuosity, tracheal
position and density of lung fields
 Rotation can obscure a
pneumothorax . Can also mimic a
mediastinal shift.
 Rotation may cause an increase in the transradiancy (blackness)
of the lung on the side to which the patient is rotated.
 Rotation will also alter the relative appearance on the hila and
can mimic hilar asymmetry.

Frontal chest x-Ray (CXR) with subject rotated to
the left. Note an enlarged heart and small left
pleural effusion. The left hemithorax is darker
than the right due to the rotation.

Chest X-ray quality - Inspiration & lung volume
Assessing inspiration:
Count ribs down to
the diaphragm.
The diaphragm
should be
intersected by:
 the 5th to 7th (right
6th anterior rib )
anterior ribs in the
mid-clavicular line or
 The 8th–10th (9th)
posterior ribs . CXR in full inspiration

If the image is acquired in the
expiratory phase or with a
poor inspiratory effort:
1. The lungs are relatively airless
and their density is increased.
2. Increase in lower zone
opacity
3. The hila are compressed and
appear more bulky
4. Exaggeration of heart size
5. Obscuration of the lung
bases.
Chest X-ray quality - Inspiration & lung volume
poor inspiratory effort
full inspiration the same patient

Chest X-ray quality - Penetration
Differential Absorption:
Penetration of the x-ray
beam is dependent on
tissue density
 Denser object = Less
beam striking the
film (more
absorption) = whiter
 Less dense = More
beam striking the
film = blacker

A well penetrated (exposed) chest X-ray :
 The end plates of the lower thoracic vertebral bodies
should be just visible through the cardiac shadow.
 The left hemidiaphragm should be visible to the edge
of the spine.

Good penetration
You should be able
to just see the
thoracic spine
through the heart

An under-penetrated film looks diffusely opaque (too
white), structures behind the heart are obscured, and
left lower lobe pathology may be easily missed.
An over-penetrated film looks diffusely lucent, the lungs
appear blacker than usual and the vascular markings and
lung detail are poorly seen.

Chest X-ray quality - Artifact
Radiographic artifact
Rotation, incomplete inspiration
and incorrect penetration. Other
radiographic artifact includes
clothing or jewellery not
removed.
Patient artifact
Poor co-operation with
positioning or movement. Very
often obesity exaggerates lung
density. Occasionally normal
anatomical structures such as hair
or skin folds can cause confusion. Hair artifact

Chest X-ray anatomy - Airways
Assessing the airways
Start your assessment of
every X-ray by looking at the
airways.
The trachea should be central
or slightly to the right.
If the trachea is deviated:
If the patient is rotated, or if
there is pathology.
If the trachea is deviated:
If it has been pushed or
pulled by a disease process.
The trachea branches at the
carina, into the left and right
main bronchi, and these can
often be followed as they
branch beyond the hila and
into the lungs.

Chest X-ray anatomy - Airways
large left pleural
effusion, and
tracheal shift away
from the effusion
Tension pneumothorax
with tracheal deviation
to right
Tracheal shift to the
right due to thyroid
enlargement
Causes of tracheal deviation:
 Ipsilateral (To pull): Collapse and Fibrosis
 Contralateral ( To push): Apical mass , Pleural effusion
and Pneumothorax

Chest X-ray anatomy - Hilar structures
The structures contributing to
hilar shadows are:
Major: Pulmonary artery and veins
 Minor: Fat, Lymph nodes and
Bronchial walls (not visible unless
abnormal)
Normal Hilum:
 Position: Left hilum is slightly
higher than the right hilum, Only in
a minority of cases the right hilus is
at the same level as the left, but
never higher.
 Shape: Concave
 Size: Similar on both sides
 Density: Almost same on both sides
Deoxygenated blood (blue
arrow) is pumped upwards out
of the right ventricle (RV) via
the main pulmonary artery
(MPA). This divides into left
(LPA) and right (RPA) which
each pass via the lung hila into
the lung tissue

Chest X-ray anatomy - Hilar structures
 The hilar points: the angle formed
by the descending upper lobe
veins, as they cross behind the
lower lobe arteries
 Not every normal patient has a
very clear hilar point on both
sides, but if they are present then
they can be useful in determining
the position of the hila.
Identify main lower lobe
pulmonary arteries: They
can be compared to a
little finger pointing
downwards and medially.

Chest X-ray anatomy - Lung zones
The chest radiograph zones:
1. Apical zone: above the
clavicles
2. Upper zone: below the
clavicles and above the
cardiac silhouette (i.e. up to
lower margin of 2nd rib )
3. Mid zone: the level of the
hilar structures (i.e. from
lower margin of 2nd rib to
lower margin of 4th rib )
4. Lower zone: the bases ( i.e. from 4th rib to diaphragm )

Chest X-ray anatomy - Pleura and pleural spaces
Trace round the entire edge
of the lung where pleural
abnormalities are seen.
Start and end at the hila
Is there pleural thickening?
Is there a pneumothorax?
The lung markings should
be visible to the chest wall
Is there an effusion? The
costophrenic angles and
hemidiaphragms should be
well defined

Chest X-ray anatomy - Pleura and pleural spaces
Costophrenic recesses and
angles:
The costophrenic angles
are limited views of the
costophrenic recess
On a frontal view the
costophrenic angles
should be sharp.
The costophrenic angles
consist of the lateral
chest wall and the dome
of each hemidiaphragm.

Chest X-ray anatomy - Lung lobes and fissures
In the right lung there
is an oblique fissure
( of ) and a horizontal
fissure ( hf ) ,
separating the lung into
three lobes - upper,
middle, and lower.
 Each lobe has its own
visceral pleural
covering.

Chest X-ray anatomy - Lung lobes and fissures
 The left lung is
divided into two
lobes, upper and
lower.
 These lobes have
their own pleural
covering and these
lie together to form
the oblique (major)
fissure ( of ).

Chest X-ray anatomy - Diaphragm
The hemidiaphragms are not
at the same level on frontal
erect inspiratory chest
radiographs, but are usually
within one rib intercostal space
height (2 cm) of each other.
The left hemidiaphragm is
usually lower than the right.
If the left hemidiaphragm is
higher than the right or the
right is higher than the left by
more than 3 cm, one of the
many causes of diaphragmatic
elevation should be considered.

Chest X-ray anatomy - Diaphragm
Hemidiaphragms - lateral
view:
 The left and right
hemidiaphragms are
almost superimposed on
a lateral view.
 Anteriorly the left
hemidiaphragm blends
with the heart and
becomes indistinct.

Chest X-ray anatomy - Heart size and contours
From superior to inferior:
1. Right paratracheal stripe:
made up of right
brachiocephalic vein and SVC
2. Arch of the azygous vein
3. Ascending aorta in older
individuals projects to the
right of the SVC
4. Superior vena cava (SVC)
5. Right atrium
6. Inferior vena cava (IVC)
The normal contours of the heart and mediastinum
(cardiomediastinal contour):
Right cardiomediastinal contour

 Left paratracheal stripe
Made up of left common
carotid artery, left subclavian
artery and the left jugular vein
 Aortic arch +/- aortic nipple
(left superior intercostal vein)
 Pulmonary artery
 Auricle of left atrium
 Left ventricle
The normal contours of the heart and mediastinum
(cardiomediastinal contour):
Left cardiomediastinal contour

Lateral view:
Anterior cardiomediastinal contour
1. Superior mediastinum
1. great vessels
2. thymus
2. Ascending aorta
3. Right ventricular outflow track
4. Right ventricle
Posterior cardiomediastinal contour
1. Left atrium and pulmonary veins
2. Right atrium
3. Inferior vena cava

Cardiothoracic ratio:
The cardiothoracic ratio
should be less than 0.5. i.e.
A+B/C<0.5
A cardiothoracic ratio > 0.5
suggests cardiomegaly in
adults
 A cardiothoracic ratio > 0.6
suggests cardiomegaly in
newborn.

 There are several structures in the superior mediastinum
that should always be checked. These include the aortic
knuckle, the aorto-pulmonary window, and the right
para-tracheal stripe.

It is a space
located between
the arch of the
aorta and the
pulmonary
arteries.
This space can be
lost as a result of
mediastinal
lymphadenopathy
(e.g. malignancy).
The aorto-pulmonary window:
Aortic knuckle (red arrow) &
Aortopulmonary window (green arrow)

Chest X-ray anatomy - Mediastinum
 In lateral CXR, mediastinum divided into :
 Superior mediastinum (S): above the
thoracic plane or the plane of Ludwig
(a horizontal line that runs from sternal
angle or angle of Louis) to the inferior
endplate of T4)
 Inferior mediastinum: below the plane of
Ludwig
 Anterior mediastinum (A): anterior to
the pericardium
 Middle mediastinum (M): within the
pericardium
 Posterior mediastinum (P): posterior to
the pericardium
 In PA view, the mediastinum is that space
between the lungs and pleural surfaces
(yellow lines).

Chest X-ray anatomy - Bones and Soft tissues
Bones:
 Ribs (anterior
and posterior)
 Clavicles and
shoulders
 Sternum
 Vertebrae
 Shoulder joints
Soft tissues :
 Breast shadows
 Skin folds
 Muscles
Check for: Symmetry, Deformities, Fractures, Masses, Calcifications
and Lytic lesions .

Chest X-ray anatomy - Lateral view
Interpretation of lateral film

Interpretation of lateral film
The clear spaces
 Retrosternal space
 Retrotracheal
space
 Retro cardiac
Vertebral
translucency
Diaphragm outline
The fissures
The trachea
The sternum

Retrosternal space
 Seen as a normal lucency
between the posterior aspect
of the sternum and anterior
aspect of the ascending aorta
 This space should be visible
and less than 2.5cm in width.
 Can be demonstrated at point
3cm below manibrium sterni
 An increased retrosternal
airspace is a reliable sign of
pulmonary emphysema, while
obliteration indicates anterior
mediastinal mass e.g.
lymphoma.

Chest X-ray anatomy: Lateral view
Vertebral translucency
 The ‘‘spine sign,’’ which
states that the normal
lateral chest film shows
increasing overall lucency
as one looks down the
thoracic vertebral bodies
from the neck to the
diaphragms.
 Causes of failure to darken
gradually above the
diaphragms:
 Pleural thickening
 Lower lobe collapse
 Mediastinal mass

Diaphragm outline
 Right
hemidiaphragm
continues
anteriorly
 left
hemidiaphragm
blends with the
heart and
becomes
indistinct
Anteriorly.

Chest X-ray anatomy - The fissures
The oblique fissures
(the major fissures or
greater fissures):
begins roughly at the
spinous process of the
T4 level of the thoracic
spine and ends at the
anterior costophrenic
angle
The right lung

The horizontal fissure
(the minor fissure):
running horizontally
from the edge of right
lung towards the right
hilum, at approximately
the level of the anterior
4th rib
The right lung
Consolidation abutting the horizontal
fissure allows it to be localized to the
right upper lobe (arrow)

The oblique fissures
(the major fissures
or greater fissures):
begins between the
spinous processes of
vertebrae T3 and T4
and ends about 5 cm
posterior to the
anterior costophrenic
angle
The left lung

How to speak - Normal CXR
This is chest radiograph, PA view with
normal exposure, no rotation and without
any apparent bony abnormality. Trachea is
placed centrally & lung fields are clear with
normal broncho-vescicular markings.
Cardiovascular silhouette is within normal
limits with normal cardiothoracic ratio.
Mediastinum, costo-phrenic, cardio-phrenic
angles, dome of diaphragm & soft tissue
shadow within normal limits.

Chest X-ray Abnormalities - Trachea
Ensure trachea is visible and in midline
1. Tracheal displacement (discussed previously)
2. Trachea normally narrows at the vocal cords
3. View the carina, angle should be between 60 –100
degrees. Beware of things that may increase this angle,
e.g. left atrial enlargement, lymph node enlargement and
left upper lobe atelectasis
4. Follow out both main stem bronchi
5. Check for tubes, foreign bodies etc.
6. If an endotracheal tube is in place, check the positioning,
the distal tip of the tube should be 5-7cm above the
carina

In this patient, the endotracheal tube is in the right
mainstem bronchus, and the left sided is not being
ventilated. That is why the left side is collapsed

Chest X-ray Abnormalities - The lung hilum
A. Hilar position:
If a hilum has moved, you should try to determine if it has
been pushed or pulled, just like you would for the
trachea.
The left hilum must never be lower than the right hilum.
Whenever a left hilum appears lower than the right hilum
– look for other evidence suggestive of:
 Collapse of either the left lower lobe or of the right
upper lobe
 Enlargement of the right hilum

A. Hilar position:
Superior displacement and
horizontalization of the right hilum
(white curved arrow) due to
atelectasis of the right upper lobe
(black arrows). the hilum (red arrow)
Left lower lobe atelectasis. The blue
arrows point to the edge of a
triangular region of atelectatic left
lower lobe. Left Hilum displaced
inferiorly. the hilum (red arrow)

B. Hilar enlargement:
May be unilateral or bilateral, symmetrical or asymmetrical

Analyze the enlargement of
hilum (if present):
1. Lymph Node enlargement:
 Lobulated appearance
(lumpy-bumpy opacity )
 Presence of calcification
within the mass
indicates usually
tuberculosis.
 Egg-shell calcification
indicates silicosis or
sarcoidosis. Calcified bilateral hilar
lymphadenopathy in
sarcoidosis

2. Arterial enlargement:
 Smooth margins
 In pulmonary arterial
hypertension the
arteries in the outer
two-thirds of each
lung are smaller than
those at the hila
(peripheral pruning)
Primary pulmonary hypertension showing
right heart enlargement and enlargement
of the main pulmonary artery and its right
and left branches.

3. Malignancy:
 Spiculated irregular or
indistinct margins
 Hilar enlargement due
to malignant lung lesion
is also associated with
superior mediastinal
lymphadenopathy. Look
at the lung fields (for
presence of tumor) and
bone/ribs for
metastasis.
This patient has a bulky right
hilum. This was shown to be due
to a bronchogenic tumour.

C. Hilar density:
May be due to :
 A mass or calcification in
the hilum
 Dense Hilum Sign:
superimposition of
another abnormal
density (pneumonia or a
mass ) in the lung or
mediastinum that
projects over the hilum
on the frontal image.
Here is increased density and
enlargement of the right hilum with
a multilobular contour. The CT
scans show enlarged mediastinal
and right hilar lymph nodes.

Dense Hilum Sign:
On the frontal (PA) image, the left hilum (red arrow)
appears denser than the right hilum (white arrow). This
may be caused by a hilar mass, but not necessarily. The
lateral view shows airspace disease (pneumonia) in the
superior segment of the left lower lobe (yellow arrow).

Chest X-ray Abnormalities - lung fields
Lung abnormalities:
Abnormal whiteness
(increased density):
Consolidation
Atelectasis
Nodule or mass
Interstitial
Abnormal blackness
(decreased density):
Cavity
Cyst
Emphysema
Assess the lungs by comparing the upper,
middle and lower lung zones on the left
and right

Chest X-ray Abnormalities - lung fields
Four patterns of
increased density:
 Consolidation
 Lobar
 Diffuse
 Multifocal ill-
defined
 Atelectasis
 Nodule or mass
 Solitary Pulmonary
Nodule
 Multiple Masses
 Interstitial
 Reticular
 Fine Nodular

lung field abnormalities - Consolidation

The key-findings on the
Ill-defined
homogeneous opacity
obscuring vessels
Silhouette sign: loss of
lung/soft tissue
interface
Air-bronchogram
Extention to the pleura
or fissure, but not
crossing it
No volume loss
May be Blunting of
costophrenic angle
X-ray are:

 Air bronchogram refers to the phenomenon of air-filled
bronchi (dark) being made visible by the opacification of
surrounding alveoli (grey/white).

Right Upper Lobe Consolidation:

Right middle Lobe Consolidation:

Right lower Lobe Consolidation:

left upper Lobe Consolidation:

Lingular consolidation:

Left lower lobe consolidation:

Lymphoma: Imaging Findings:
 Mediastinal widening due to
mediastinal lymphadenopathy
 Parenchymal lung involvement:
 Multiple nodules
 Consolidation with an
air - bronchogram
 Segmental or lobar
atelectasis
 Pleural effusions (Mostly
small, unilateral, and
exudative)
 Destructive rib or vertebral
body lesion
Chest X-ray reveals multiple
scattered consolidation lesions
involving both lungs

Tuberculosis (TB): Primary pulmonary tuberculosis:
Imaging Findings:
 Patchy or lobar consolidation
 Cavitation (uncommon)
 Caseating granuloma
(tuberculoma) which usually
calcifies (known as a Ghon
lesion)
 Ipsilateral hilar and
mediastinal (paratracheal)
lymphadenopathy, usually
right sided.
 Calcification of nodes
 Atelectasis
 Pleural effusions
Chest X-ray shows right upper lobe
and left midzone consolidation
and adenopathy.

Consolidation - Tuberculosis
Post-primary pulmonary: Imaging Findings:
 Almost always affect:
1. Posterior segments of the
upper lobes
2. Superior segments of the
lower lobes
 Patchy consolidation
 Poorly defined linear and
nodular opacities
 Cavitation, Aspergillomas,
fibrosis and Bronchiectasis
 pleural effusion
 Hilar nodal enlargement
 Lobar consolidation,
tuberculoma and miliary TB
Patchy bilateral opacification of the
upper lung lobes with cavitation most
marked on the left (arrow)

Consolidation - Tuberculosis
Tuberculoma and Miliary Tuberculosis: Imaging Findings:
 Tuberculoma and miliary
tuberculosis are rare
 Miliary deposits are seen
both in primary and post-
primary tuberculosis. It
appear as 1-3 mm diameter
nodules, which are uniform in
size and uniformly distributed
 Tuberculomas are usually
found as single nodules and
they may include a cavity or a
calcification with sharp
margins. They are usually
found in the upper lobes
Miliary Tuberculosis

Aspergillomas:
 Mass-like fungus balls of Aspergillus fumigatus, occur in patients
with normal immunity but with pre-existing cavities:
 pulmonary tuberculosis
 pulmonary sarcoidosis
 bronchiectasis
 bronchogenic cyst
 pulmonary sequestration
 Pneumocystis pneumonia (PCP)
associated pneumatocoeles
 Imaging Findings: Air crescent sign :
Rounded or ovoid soft tissue attenuating
masses located in a surrounding cavity
and outlined by a crescent of air.
Differential diagnosis (DD); hydatid cyst,
bronchogenic carcinoma and PCP.
Rounded density with an
air crescent

Aspiration Pneumonitis and Pneumonia: Imaging Findings:
 Chest x-ray shows an infiltrate,
frequently in the superior or
posterior basal segments of a
lower lobe or the posterior
segment of an upper lobe (The
right lower lobe is the most
frequent location).
 Multifocal patchy infiltrates
 Bilateral perihilar, ill-defined,
alveolar consolidations and
aspiration-related lung abscess
 Interstitial or nodular
infiltrates, pleural effusion
Typically localized pneumonia in
the right lower lobe.

Consolidation - Lung infarction
Hampton’s Hump: consists of a pleural based
shallow, wedge-shaped consolidation in the lung
periphery with the base against the pleural surface

Klebsiella pneumonia (Friedländer’s pneumonia):
Imaging Findings:
 Usually involves one of
the upper lobes
 Homogeneous,
nonsegmental, lobar
consolidation
 Bulging Fissure Sign:
bulging of usually minor
fissure from heavy,
exudate ( arrow)
 Lung abscess (es)
 Pleural effusion (70%)
and/or empyema

Consolidation - Cardiogenic pulmonary edema
Consolidation due to Congestive Heart Failure (CHF) :

Stage I CHF – Redistribution:
Redistribution of the pulmonary veins. This is know as
cephalization (blue arrow) because the pulmonary veins
of the superior zone dilate due to increased pressure.
An increase in width of the vascular pedicle (red arrows)

 The vascular pedicle is bordered on the right by the
superior vena cava and on the left by the left subclavian
artery origin

Stage II CHF - Interstitial edema Characterized by:
1. Kerley’s A lines: extend radially from the hilum to the
upper lobes; represent thickening of the interlobular
septa that contain lymphatic connections.

2. Kerley’s B lines: are short horizontal lines situated
perpendicularly to the pleural surface at the lung base;
they represent edema of the interlobular septa.

3. Thickening of the bronchial walls (peribronchial cuffing)
and as loss of definition of these vessels (perihilar haze).

4. Fluid in the major or minor fissure (shown here)
produces thickening of the fissure beyond the pencil-
point thickness it can normally attain

Stage III CHF - Alveolar edema Characterized by:
Alveolar edema with
perihilar consolidations
and air bronchograms
( Bat's wing or butterfly
pulmonary opacities )
(yellow arrows)
Pleural fluid (blue arrow)
Prominent azygos vein
and increased width of
the vascular pedicle (red
arrow)
An enlarged cardiac silhouette (arrow heads).

 Bat's wing appearance:
A bilateral perihilar distribution of consolidation.
 Reverse bat's wing appearance:
Peripheral or subpleural consolidation

Reverse bat's wing appearance
In Chronic eosinophilic pneumonia

Adult Respiratory Distress Syndrome ( ARDS )
ARDS versus Congestive Heart Failure:
Diffuse bilateral
patchy infiltrates
More uniform
opacification
Homogenously
distributed
No cardiomegaly
No cephalization
Usually no pleural
effusion or Kerley
B lines

Pneumonia can be classified histologically into lobar, lobular,
bronchopneumonia, and interstitial.
Bronchopneumonia characterised by:
 Multiple small nodular
or reticulonodular
opacities which tend to
be patchy and/or
confluent.
 The distribution is often
bilateral and
asymmetric, and
predominantly involves
the lung bases

Atypical pneumonia (AP) characterised by:
 Patchy reticular or reticulonodular opacities
 Subsegmental and sometimes segmental atelectasis
 Seen in the perihilar lung.
(AP) Legionella pneumonia:
 Multifocal and bilateral patchy
infiltrate
 Middle and lower zone
predominance
 Pleural effusions can be common
 Associated hilar adenopathy
may be present.
 Cavitation and a mass-like
appearance
Legionella pneumonia.
Chest radiograph shows
dense consolidation in
both lower lobes.

(AP) Mycoplasma pneumonia characterised by:
Peribronchial and perivascular interstitial infiltrates.
Reticular densities most common
Airspace consolidation.
Reticulonodular
opacification
Nodular or mass-like
opacification
Bilateral peribronchial
perivascular interstitial
infiltrates
Common Lower lobes
affection
Mycoplasma pneumonia .The chest
radiograph shows patchy non-
segmental opacities bilaterally.

(AP) Chlamydia pneumonia characterised by:
Alveolar infiltrates or bronchopneumonia
Findings are often limited to a single lobe
lower lobe involvement
occurring more frequently
Up to 25% of patients may
have a small to moderate-
sized pleural effusion
Interstitial pneumonia is rare
Hilar or mediastinal
lymphadenopathy is
uncommon
Chlamydia pneumonia .
Consolidation within the superior
segment of the left lower lobe.

(AP) Viral pneumonia characterised by:
 Patchy, unilateral, or bilateral:
 consolidations and
ground-glass opacity or
 poorly defined centrilobular
nodules.
 Peribronchial thickening
 Areas of atelectasis or
air trapping
 Pleural effusion, hilar
lymphadenopathy and
pneumothorax are
uncommon findings. Respiratory syncytial virus
(RSV). Bilateral upper zone
patchy airspace opacification.

(AP) Covid-19 pneumonia characterised by:
 Normal in up to 63% in the early stages
 Ground glass (68.5%), coarse horizontal linear opacities, and
consolidation. These are more likely to be peripheral and in
the lower zones
 Bilateral lung involvement is
most common
 Pleural effusion is rare (3%)
Covid-19 pneumonia. ground glass
opacity in both mid and lower zones of
the lungs, which is predominantly
peripheral (white arrows) with
preservation of lung marking. Linear
opacity can be seen in the periphery of
the left mid zone (black arrow)

(AP) Fungal Pneumonia
characterised by:
Patchy infiltrate, nodules,
consolidation, cavitation,
or pleural effusion may be
observed.
Mediastinal adenopathy is
common in endemic fungal
pneumonias.
 The adenopathy may be
either unilateral or bilateral.
Miliary infiltration occurs in
patients with disseminated
disease.
Fungal Pneumonia . multiple
pulmonary nodules

E-Cigarette or Vaping Product-Associated Lung Injury:
Bilateral lower-lobe predominant hazy (ground glass) and
consolidative opacities
Rarely:
 Pleural effusion
 Pneumothorax
 pneumomediastinum
E-cigarette or
Vaping-product
associated lung injury,
showing significant
bilateral alveolar opacities

Wegener's granulomatosis characterized by:
 Nodules or mass lesions, which may cavitate
 Fleeting focal infiltrates (lung consolidation )

 It is a congenital abnormality. A
nonfunctioning part of the lung lacks
communication with the bronchial
tree and receives arterial blood
supply from the systemic circulation.
 The plain X-ray often shows a
triangular or oval-shaped, basal,
posterior lung mass, or, less
commonly, as a cyst more on the left
 An infected sequestration may be
associated with a parapneumonic
effusion, and may contain one or
more fluid levels.
Pulmonary sequestration: This is an uncommon cause of lobar
consolidation.
Chest radiograph showing left
lower lobe consolidation
(arrow)

Eosinophilic pneumonia (EP):
 Acute EP : A pattern consistent
with pulmonary edema, with
extensive airspace opacity,
interlobular septal thickening (ie,
Kerley B-lines), and pleural
effusions. The infiltrates are
diffuse and not peripherally
based.
 Chronic EP : Nonsegmental
peripheral airspace consolidation
(“photographic negative shadow
of pulmonary oedema” - reverse
bat wing appearance) involving
mainly the upper lobes .
Chronic EP: The chest x-ray
shows bilateral peripheral
patchy infiltrates with relative
sparing of the lower lobes.

Septic emboli:
Usually present as
multiple ill-defined
densities, which are
probably
consolidations.
In about 50%
cavitation is seen.

lung field abnormalities - Interstitial disease
 On a CXR the most common pattern is reticular.
 The ground-glass pattern is frequently not detected.
 The cystic pattern is also difficult to appreciate.
 High-resolution computed tomography (HRCT) has the ability
to better define diseases that have similar CXR patterns.
 There are many causes. For example:

lung field abnormalities - Alveolar vs. Interstitial
 Alveolar = air sacs
 Radiolucent
 Can contain blood,
mucous, tumor, or
edema (“airless lung”)
 Interstitial = vessels,
lymphatics, bronchi, and
connective tissue
Radiodense
Interstitial disease:
prominent lung markings
with aerated lungs

Linear Pattern:
There is thickening of the
interlobular septa (contain
pulmonary veins and
lymphatics ), producing
Kerley lines.
DD of Kerly Lines:
( Pulmonary edema is the
most common cause, Mitral
stenosis, Lymphangitic
carcinomatosis, Malignant
lymphoma, Congenital
lymphangiectasia, Idiopathic
pulmonary fibrosis, Pneumoconiosis and Sarcoidosis )

Reticular Pattern:
Fine "ground-glass" (1-2
mm): e.g. interstitial
pulmonary oedema
Medium "honeycombing"
(3-10 mm): commonly seen
in pulmonary fibrosis
Coarse (> 10 mm): cystic
Spaces caused by
parenchymal destruction,
e.g. usual interstitial
pneumonia, pulmonary
sarcoidosis, pulmonary
Langerhans cell histiocytosis

Causes of Reticular Pattern:
 Pulmonary edema (heart failure,
fluid overload, nephropathy)
 Infection (viral, mycoplasma,
Pneumocystis, malaria)
 Post-infectious scarring
(tuberculosis, histoplasmosis,
coccidioidomycosis,
Pneumocystis)
 Mitral valve disease
 Collagen vascular disorders
 Granulomatous disease
(pulmonary sarcoidosis,
eosinophilic granuloma)
 Drug reactions (e.g. amiodarone)
 Pulmonary neoplasms
(lymphangitis carcinomatosis,
pulmonary lymphoma)
 Inhalational lung disease
(asbestosis, silicosis, coal
workers pneumoconiosis,
hypersensitivity pneumonitis,
chronic aspiration pneumonia)
 Idiopathic (usual interstitial
pneumonia,
lymphangioleiomyomatosis,
tuberous sclerosis,
neurofibromatosis,
amyloidosis )

Nodular pattern:
 A nodular pattern consists
of multiple round
opacities, generally
ranging in diameter from
1 mm to 1 cm
 Nodular opacities may be:
 Miliary nodules: <2 mm
 Pulmonary
micronodule: 2-7 mm
 Pulmonary nodule:
7-30 mm
 Pulmonary mass:
>30mm

Causes of Miliary opacities :
 Infection
 tuberculosis
 fungal (often febrile)
 healed varicella pneumonia
 viral pneumonitis
 nocardosis
 salmonella
 Miliary metastases
 thyroid carcinoma
 renal cell carcinoma
 breast carcinoma
 malignant melanoma
 pancreatic neoplasms
 osteosarcoma
 trophoblastic disease
 Sarcoidosis
 Pneumoconioses
 silicosis
 coal workers pneumoconiosis
 Pulmonary haemosiderosis
 Hypersensitivity pneumonitis
 Langerhans cell histiocytosis
 pulmonary alveolar
proteinosis

Causes of Calcified pulmonary nodules:
 Healed infection
 Calcified granulomata, e.g.
 Thoracic histoplasmosis
 Recovered miliary TB
 Healed varicella pneumonia
 Pneumoconioseses
 silicosis
 coalworker's pneuomconiosis
 Pulmonary hamartomas
 Metastatic pulmonary calcification
 Chronic renal failure
 Multiple myeloma
 Secondary hyperparathyroidism
 Massive osteolytic metastases
 IV calcium therapy
 Pulmonary haemosiderosis
 idiopathic pulmonary
haemosiderosis
 Mitral stenosis
 Goodpasture syndrome
 Pulmonary alveolar
microlithiasis
 Sarcoidosis
 Calcified pulmonary
metastases
 Pulmonary amyloidosis
 Pulmonary hyalinizing
granuloma
 Calcifying fibrous
pseudotumour of lung

 A reticulonodular
pattern results from a
combination of reticular
and nodular opacities.
 A differential diagnosis
should be developed
based on the
predominant pattern.
 If there is no
predominant pattern,
causes of both nodular
and reticular patterns
should be considered.
 Causes: the same disorders as reticular patterns
Reticulonodular pattern:

Ground-glass appearance
A hazy area of increased
attenuation in the lung with
preserved bronchial and
vascular markings.
Aetiology:
 Normal expiration
 Partial filling of air spaces
 Partial collapse of alveoli
 Interstitial thickening
 Inflammation
 Oedema
 Fibrosis
 Neoplasm
Perihilar ground-glass
appearance in the shape of
bats-wings

A lung cyst:
an air filled structure and occurs without associated pulmonary
emphysema with perceptible wall typically 1 mm in thickness but can
be up to 4 mm. The diameter of a lung cyst is usually < 1 cm.
Aetiology:
 Sjogren syndrome
 light chain deposition disease
 Amyloidosis
Others:
 Birt-Hogg-Dubé syndrome
 Pulmonary trauma
 Congenital cystic lung disease
(congenital pulmonary airway
malformation, pulmonary
sequestration, bronchogenic cyst)
 Tracheobronchial papillomatosis
 Hydatid Cyst
Interstitial disease:
 Pulmonary Langerhans cell
histiocytosis
 lymphangioleiomyomatosis with
or without tuberous sclerosis
 Interstitial pneumonia (DIP, LIP)
 Pneumatocele
 Sarcoidosis
 Neurofibromatosis
 Cystic bronchiectasis
 PCP
 Honeycombing in UIP

Hypersensitivity pneumonitis (HP) - (acute & Subacute):
 PCX-ray may be normal
 PCX-ray commonly shows
a bilateral diffuse micro nodular
infiltrate, usually dense towards
hila, have a predilection for the
midzones or lower zones. An
irregular and linear infiltrate
may be present in lower zones.
 Acute severe attack : a pattern
of diffuse airspace disease or a
ground-glass pattern mimicking
that of pulmonary edema or,
more rarely, as consolidation.
Bilateral reticulonodular
interstitial infiltration
secondary to subacute
hypersensitivity pneumonitis.

Hypersensitivity pneumonitis (HP) - (chronic):
 Pulmonary fibrosis affects
upper zones predominantly,
loss of lung volume.
 Reticular pattern and
honeycombing, more severe
in the upper lobes than in
the lower ones
 Larger ring shadows 1-4 mm
in diameter are due to bullae,
blebs, cysts, or bronchiectasis.
 Parallel line shadows are
caused by bronchiectasis or
bronchial wall thickening
Chronic HP. Diffuse reticular pattern, more
severe in the upper lobes with a decrease
of lung volume. Note also the ground glass
opacity present in the inferior lobes,
especially on the left inferior

Sarcoidosis; classified by chest x-ray into 5 stages :
 Stage 0: normal chest
radiograph
 Stage I: hilar or
mediastinal nodal
enlargement only
 Stage II: nodal
enlargement and
parenchymal disease
 Stage III: parenchymal
disease only
 Stage IV: end-stage
lung (pulmonary
fibrosis)

Radiographic varieties of Sarcoidosis :
 Hilar and mediastinal lymphadenopathy: Garland triad, also known
as the 1-2-3 sign is bilateral hilar and right paratracheal
lymphadenopathy.
 Dystrophic calcification of involved lymph nodes: Calcification can
be amorphous, punctate, popcorn like, or eggshell.
 Parenchymal changes: including fine nodular; reticulonodular;
acinar (poorly marginated, small to large nodules or coalescent
opacities); and, rarely, focal (solitary nodule or mass).
 Mycetomas: in stage IV sarcoidosis and apical bullous disease
 In stage IV : when fibrosis supervenes, hilar retraction, decreased
lung volume, and honeycomb lung may be present. Bullous disease,
air trapping and diaphragmatic tenting may also be seen.
 Pulmonary hypertension may develop: Prominent main pulmonary
artery, enlarged right and left pulmonary arteries, right ventricular
enlargement, and attenuation of peripheral vessels.

 Can be even normal in patients
with very early disease
 In advanced disease:
 Decreased lung volumes
 Basal fine to coarse
reticulation due to more
extensive involvement of the
lower lobes
 Honeycomb Lung and traction
bronchiectasis
 The major fissure is shifted
inferiorly which is best seen on
the lateral chest radiograph.
Usual interstitial pneumonia (UIP):
 Plain film features are nonspecific
Usual interstitial pneumonia
(UIP). X- ray show reticular
opacities with apibasal gradient

Usual interstitial pneumonia (UIP):
 Honeycombing:
Chest radiograph demonstrates coarse
bibasilar reticular interstitial disease
(honeycomping) (red arrows)
The radiographic appearance
of honeycombing comprises
reticular densities caused by
the thick walls of the cysts.
Honeycomping

Bronchiectasis:
 CXR may be normal
 Volume loss
 Increased pulmonary markings
 Indistinct vessel margins due
to peribronchial fibrosis.
 Tram lines: dilated and thickened
airways
 Ring shadows: thickened and
abnormally dilated bronchial walls
 Clusters of cysts in Cystic type
 Dextrocardia (Immotile cilia
syndrome)
 Mucus plugging (ﬁnger-in-glove)
appearance
 Atelectasis or diffuse lung fibrosis
Tram-Track sign

Bronchiectasis:
Cystic bronchiectasis with
multiple cystic airspaces
Ring shadow ( red arrow) & Tram
lines ( yellow arrow)

Bronchiectasis: Location:
 Allergic bronchopulmonary
aspergillosis – central
 Childhood viral infections –
Lower lobe predominance
 Mounier-Kuhn syndrome –
First to fourth order bronchi
 Mycobacterial avium complex
- Right middle lobe and lingual
 Primary ciliary dyskinesia –
Fifty percent associated with
situs inversus, middle lobe,
and lingular predominance
 Cystic fibrosis - Upper lobe,
particularly right upper lobe
 Postprimary mycobacterial
tuberculosis (traction
bronchiectasis) – Apical
and posterior segments of
upper lobes
 Sarcoidosis (traction
bronchiectasis) – Upper
lobe predominance
 Usual interstitial
pneumonitis (commonest
cause of traction
bronchiectasis) - Lower
lobe predominance, worse
peripherally

Allergic bronchopulmonary aspergillosis (ABPA):
 Early in the disease : normal
CXR, or only demonstrate
changes of asthma.
 Fleeting shadows of
transient pulmonary
infiltrates represent
eosinophilic pneumonia.
 Eventually, bronchiectasis
may be evident.
 Mucoid impaction in dilated
bronchi can appear mass-
like or sausage-shaped or
branching opacities (finger
in glove sign).
 Pulmonary collapse.
"Glove like" opacity in the right upper
zone (yellow dotted line) represents
sputum plugged bronchiectasis

Pneumocystis Carinii Pneumonia (PCP) - CXR findings:
 Bilateral, diffuse, often perihilar
finely granular / reticular interstitial
airspace infiltrates.
 Isolated lobar or focal consolidation,
particularly with an upper-lobe
predominance
 Cavitation
 Cystic lung disease and spontaneous
pneumothorax.
 Miliary nodularity, bronchiectasis,
endobronchial lesions
 Pleural effusion and hilar
lymphadenopathy are uncommon
 CXR may be normal
Typical bilateral air-space
consolidation of PCP in
acquired immunodeficiency
virus infection.

Lymphangitic carcinomatosis:
 The term given to tumour spread
through the lymphatics of the lung,
and is most commonly seen
secondary to adenocarcinoma e.g.
breast cancer, bronchogenic
adenocarcinoma, colon cancer,
stomach cancer, prostate cancer,
cervical cancer, thyroid cancer, etc.
 CXR may be normal or Appears as
reticular or reticulonodular
opacification, often with associated
septal lines (Kerley A and B lines),
peribronchial cuffing, pleural
effusions, and mediastinal and/or
hilar lymphadenopathy
Lymphangitic carcinomatosis.
The radiograph
like in the case of interstitial
pulmonary oedema

Silicosis:
1. Acute silicosis (silicoproteinosis):
Large bilateral perihiliar consolidation
or ground glass opacities.
2. Chronic simple silicosis
(common type ): CXR shows multiple
nodular opacities:
 Well-defined and uniform in shape
and attenuation
 From 1 to 10 mm in diameter
 Predominantly located in the upper
lobe and posterior portion of the lung
 Nodules may Calcify
 Lymph node enlargement common:
Eggshell calcification of hilar nodes
(5%), DD: Sarcoidosis
Silicosis features a diffuse
micronodular lung disease
with an upper lobe
predominance

Interstitial disease - Silicosis
3. Complicated silicosis
(progressive massive fibrosis
(PMF), or conglomerate
silicosis): CXR shows large
symmetric bilateral opacities
that are:
 1 cm or more in diameter and
with an irregular margin
 Usually in mid-zone or
periphery of upper lobes
 Compensatory emphysema
occurs in lower lung fields.
 Progressive Massive Fibrosis
(PMF) with scarring and
retraction of hila upwards.
Progressive Massive Fibrosis. There are
conglomerate soft-tissue densities in
both upper lobes (black arrows) with
linear scarring leading from the lower
lobes (white arrows).

Interstitial disease - Silicosis
4.Complicated silicosis : Complicated
by tuberculous (Silicotuberculosis),
non-tuberculous mycobacterial,
and fungal infection, certain
autoimmune diseases, and lung
cancer.
Eggshell node calcification in silicosis
Silicotuberculosis, with bilateral
conglomerate disease. Several
cavities are present in the left upper
lobe

lung field abnormalities - Atelectasis
CXR show direct and indirect signs of lobar collapse:
 Direct signs include displacement of fissures and opacification of
the collapsed lobe.
 Indirect signs include the following:
 Displacement of the hilum
 Mediastinal shift toward the side of collapse
 Loss of volume in the ipsilateral hemithorax
 Elevation of the ipsilateral diaphragm
 Crowding of the ribs
 Compensatory hyperlucency of the remaining lobes
 Silhouetting of the diaphragm or heart border
 Atelectasis can be sub-categorized by morphology as follows:
 linear (plate, band, discoid, subsegmental) atelectasis
 lobar atelectasis
 segmental and subsegmental atelectasis
 round atelectasis

lung field abnormalities – Atelectasis
Complete atelectasis: Characterized by:
Opacification of the entire hemithorax
An ipsilateral shift of the mediastinum.

Increased density in the upper medial
aspect of the right hemithorax
 Elevation of the horizontal fissure
 Loss of the normal right medial
cardiomediastinal contour
 Elevation of the right hilum
 Hyperinflation of the right middle and
lower lobe result in increased
translucency of the mid and lower
parts of the right lung
 Right diaphragmatic tenting
 Non-specific signs :
 Elevation of the hemidiaphragm
 Crowding of the right sided ribs
 Shift of the mediastinum and trachea to the right
Lobar atelectasis: Right upper lobe collapse:

Atelectasis - Lobar atelectasis
Right upper lobe collapse:  The Golden S-sign (or reverse
S-sign of Golden): is seen on
PA view and the appearance
is that of right upper lobar
collapse with a central mass
expanding the hilum.
 On the lateral projection it is
harder to identify. Elevation
of the horizontal fissure and
upper part of the oblique
fissure may be visible.

Right middle lobe collapse:
 On lateral projection, right
middle lobe collapse is
usually relatively easy to
identify,
 Appearing as a triangular
opacity in the anterior
aspect of the chest overlying
the cardiac shadow.
 The horizontal fissure is
displaced inferiorly and the
inferior part of the oblique
fissure, displaced
anterosuperiorly.

Right middle lobe collapse:
On frontal CXR, the findings are more
subtle:
 The normal horizontal fissure is no
longer visible (as it rotates down)
 Blurring of the right heart border
(silhouette sign) (in atelectasis as
well as consolidation)
 Non-specific signs may be subtle or
absent due to the small size of the
right middle lobe :
 Elevation of the hemidiaphragm
 Crowding of the right sided ribs
 Shift of the mediastinum to the right
 linear opacities in the lobe suggest that the collapse is chronic
(right middle lobe syndrome), with associated bronchiectasis.

Right lower lobe collapse:
On frontal CXR, the findings :
 Increased opacity (triangular in
shape) at the medial base of the
right lung
 Obliteration of the silhouette of
the right hemidiaphragm
 The right hilum is depressed
 Descending right lower lobe
pulmonary artery is not visualized
 Right heart border maintained.
Elevation of the hemidiaphragm
Crowding of the right sided ribs
Shift of the mediastinum to right
The collapsed right lower lobe
is a triangular opacity (orange
arrows).The right
hemidiaphragmatic outline is
lost (blue dashed line).

Right lower lobe collapse:
On lateral projection:
 The right
hemidiaphragmatic
outline is lost posteriorly
 The lower thoracic
vertebrae appear denser
than normal (they are
usually more radiolucent
than the upper
vertebrae) The collapsed right lower lobe a
triangular opacity (orange arrows).
The right hemidiaphragmatic
outline is lost (blue dashed line).

Left upper lobe collapse:
 Hazy or 'Veil-like' opacification of
the left hemithorax
 Right heart border not visible
 The left hemidiaphragm is still
visible
 Near-horizontal course of the left
main bronchus
 The luftsichel sign (next)
 Elevation of the hemidiaphragm
'peaked' or 'tented‘
hemidiaphragm: juxtaphrenic peak
sign
Crowding of the left sided ribs
Shift of the mediastinum to the left
Left upper lobe collapse: Notice
the ovoid density at the left
hilum, CT confirmed a large left
hilar mass, which occluded the
left upper lobe bronchus

 The luftsichel sign:
In some cases the
hyperexpanded superior
segment of the left lower
lobe insinuates itself
between the left upper
lobe and the superior
mediastinum, sharply
silhouetting the aortic
arch and resulting in a
lucency medially ( red
arrow ).

On lateral projections:
 Increase in the
retrosternal opacity.
 left lower lobe is
hyperexpanded and
the oblique fissure
displaced anteriorly
(arrows).

Lobar Atelectasis - Left upper lobe collapse
Lingular collapse:
 The lingula collapses inferiorly and medially
 This produces an opacity in contact with the left heart border,
which causes loss of the normal silhouette
Lingular collapse. (A) Frontal view of isolated collapse of the lingular
segments of the left upper lobe showing loss of clarity of the left
heart border and a raised hemidiaphragm. (B) The similarity to a right
middle lobe collapse can be appreciated on the lateral view.

Left lower lobe collapse:
1. Triangular opacity in the
posteromedial aspect of left lung
2. Edge of collapsed lung may
create a 'double cardiac contour'
3. left hilum will be depressed
4. loss of the normal left
hemidaphgragmatic outline
5. loss of the outline of the
descending aorta
6. Non-specific signs :
 Elevation of the hemidiaphragm
 Crowding of the left sided ribs
 Shift of the mediastinum to left

Left lower lobe collapse:
7. The flat waist sign refers to flattening
of the contours of the aortic arch and
adjacent main pulmonary artery. It is
seen in severe left lower lobe collapse
and is caused by leftward
displacement and rotation of the
heart.
8. On lateral projection:
 The left hemidiaphragmatic outline
is lost posteriorly
 The lower thoracic vertebrae appear
denser than normal (they are usually
more radiolucent than the upper
vertebrae)

Rounded atelectasis:
 Classically associated with
asbestos exposure
 It is typically found in lower
lung lobes, particularly in
posterior regions
 Has the form of peripheral
round, oval or fusiform lesion
of diffuse outline.
 The size of the lesion ranges
from 2.5 to 8 cm.
 Pleural thickening at the level
of atelectasis is typical.
 The volume of the affected
lobe is reduced
Posteroanterior chest radiography:
peripheral, well-defined opacity (round
atelectasis).

Segmental atelectasis:
 Collapse of one or several
segments of a lung lobe.
 It is a morphological subtype
of lung atelectasis.
 It is better appreciated on CT
and Its radiographic
appearance can range from
being a thin linear to a wedge
shaped opacity then does not
abut an interlobar fissure.
Plain radiograph: shows a band-
like opacity with well-defined
borders, perpendicular to costal
surface, located in the left upper
lobe.

Plate-like atelectasis due to poor inspiration in a
patient who had abdominal surgery
Plate-like/subsegmental atelectasis:
 Seen in smokers, elderly, after abdominal surgery, patients in the
ICU and in pulmonary embolism
 linear shadows of increased density at the lung bases, usually
horizontal, measure 1-3 mm in thickness and are only a few cm long

Cicacitration atelectasis:
 Atelectasis can be the result of fibrosis of lung tissue.
 Seen after radiotherapy and in chronic infection, especially TB.
Atelectasis of the right upper lobe as a result of TB. Notice the
deviation of the trachea. There is also some atelectasis of the left
upper lobe, which results in a high position of the left pulmonary
artery as seen on the lateral view (red arrow)

lung field abnormalities - Nodules and Masses
A solitary pulmonary nodule:
Defined as a discrete, well-marginated, rounded opacity less than or
equal to 3 cm in diameter that is completely surrounded by lung
parenchyma, does not touch the hilum or mediastinum, and is not
associated with adenopathy, atelectasis, or pleural effusion.

A solitary pulmonary nodule: Differential diagnosis:
 Congenital
 Arteriovenous malformation
 Lung cyst and Intrapulmonary
Bronchogenic Cyst
 Bronchial atresia with mucoid
impaction
 Miscellaneous
 Hydatid cyst
 Pulmonary infarct
 Intrapulmonary lymph node
 Mucoid impaction
 Pulmonary haematoma
 Pulmonary amyloidosis
 Fungal infection
 Atelectasis
 Wegener granulomatosis
 Neoplastic
 Malignant
• Bronchogenic carcinoma
• Solitary metastasis
• Lymphoma
• Carcinoid tumours
• Sarcoma
 Benign
• Pulmonary hamartoma
• Pulmonary chondroma
 Inflammatory
 Granuloma (e.g. TB)
 lung abscess
 Rheumatoid nodule
 Plasma cell granuloma
 Round pneumonia

Other causes :
 Hyperdense pulmonary mass:
(a pulmonary mass with internal
calcification)
 Cavitating pulmonary mass:
(gas-filled areas of the lung in
the center of the mass. They are
typically thick walled and their
walls must be greater than 2-5
mm. They may be filled with air
as well as fluid and may also
demonstrate air-fluid levels).
A Pulmonary mass:
It is an area of pulmonary opacification that measures more than
3 cm. The commonest cause for a pulmonary mass is lung cancer.

Hyperdense pulmonary mass:
They include:
 Granuloma: most common
 Pulmonary hamartoma
 Bronchogenic carcinoma
 Bronchogenic cyst
 Carcinoid tumours
 Pulmonary metastases
 Dystrophic calcification:
 Papillary thyroid carcinoma
 Giant cell tumour of bone
 Synovial sarcoma
 Bone forming / cartilage
mineralisation:
 Osteosarcoma
 Chondrosarcoma
A solitary well marginated
homogeneous radiodensity is seen in
the right upper zone with focal central
area of increased density within.

lung field abnormalities - Cavities
Pulmonary cavities :
Are gas-filled areas of
the lung in the center
of a nodule, mass or
area of consolidation.
They are typically thick
walled and their walls
must be greater than
2-5 mm.
They may be filled with
air as well as fluid and
may also demonstrate
air-fluid levels.

Pulmonary cavities: A helpful mnemonic is CAVITY:
 I: infection (bacterial/fungal)
 Pulmonary abscess
 Cavitating pneumonia
 Pulmonary tuberculosis
 Septic pulmonary emboli
 T: trauma - pneumatocoeles
 Y: youth (not true "cavity")
 Congenital cystic
adenomatoid malformation
(CCAM)
 Pulmonary sequestration
 Bronchogenic cyst
 C: cancer
 Bronchogenic carcinoma:
(especially squamous cell
carcinoma)
 Cavitatory metastasis(es):
 Squamous cell carcinoma
 Adenocarcinoma, e.g.
gastrointestinal tract, breast
 Sarcoma
 A: autoimmune; granulomas:
 Wegener's granulomatosis
 Rheumatoid nodules.
 V: vascular (both bland and
septic pulmonary embolus)

 Multicystic mass with air in cysts
 CXR in type I ( large (2-10 cm)
cysts ) and II (small (< 2 cm)
cysts) CCAM may demonstrate a
multicystic (air-filled) lesion.
 Type III ( microcysts ) CCAM
appear solid.
 Large lesions may cause mass
effect with resultant, mediastinal
shift, and depression and even
inversion of the diaphragm.
 The cysts may be completely or
partially fluid filled, in which case
the lesion may appear solid or
with air fluid levels.
Congenital cystic adenomatoid malformation (CCAM):
Multiloculated cystic lesion in
right hemithorax with marked
mediastinal shift to the left.

 It can be pulmonary 10-15% or
Mediastinal 65-90%
 Usually in the medial 1/3 of lungs
 With a lower lobe predilection
 Mediastinal cysts are visualized as
a mediastinal mass (image 1)
 Intrapulmonary cysts usually present
as a solitary pulmonary nodule unless
the cyst contains air.
 Cysts are usually fluid filled,
occasionally a communication may
develop following infection or
intervention, resulting in an air-filled
cystic +/- an air-fluid level (image 2)
Bronchogenic cyst: During development a portion of the tracheo-
bronchial tree gets separated. CXR :

lung field abnormalities - Decreased density
Unilateral hypertranslucent hemithorax: potential causes:
 Pulmonary (ventilation)
 Pulmonary emphysema
 Congenital lobar overinflation
 Unilateral bullus/bullae
 Compensatory hyperinflation
 Airway obstruction e.g.
bronchial compression and
endobronchial obstruction
 Swyer-James-MacLeod
syndrome
 Unilateral lung transplant
 Pleura and pleural space
 Pneumothorax
 Pleural effusion (contralateral)
 Rotation:
 Poor patient positioning
 Scoliosis
 Chest wall defect
 Mastectomy
 Poland syndrome (absent
pectoralis major muscle)
 Mediastinal
 Mediastinal fibrosis
 Vascular (perfusion)
 Pulmonary embolism i.e.
Westermark sign
 Congenital heart disease
 Unilateral absence of pulmonary
artery or hypoplasia or stenosis
 Shunt (e.g. Blalock-Taussig)

Pulmonary emphysema:
1. Hyperinflation
 Flattened hemidiaphragm (s):
most reliable sign
 Increased and usually irregular
radiolucency of the lungs
 Increased retrosternal airspace
 Increased antero-posterior
diameter
 Sternal bowing
 Obtuse costophrenic angle on
posteroanterior or lateral film.
 Widely spaced ribs
 A narrow mediastinum
 Low flattened diaphragm

Pulmonary emphysema:
2. Vascular changes
 Paucity of blood vessels,
often distorted
 Pulmonary arterial
hypertension:
 Prominence of the
pulmonary hilum and
enlargement of the main
pulmonary arteries.
 Right ventricular
enlargement: encroachment
into the retrosternal space on
a lateral chest film
 Pruning of peripheral vessels

Decreased density - Pulmonary emphysema
Flat diaphragm are
present when the
maximum
perpendicular height
(red line) from the
superior border of the
diaphragm to a line
drawn between the
costophrenic and
cardiophrenic angles in
PA view or between
the costophrenic and
sternophrenic angles in
lateral view (blue line)
is less than 1.5 cm.

 Air within pulmonary interstitium &
lymphatics
 New bubbly linear, oval, or spherical
cystic lucencies within lung of intubated
premature infant
 Small interstitial lucencies > > large
focal/multifocal cysts
 Affected segment is often
hyperexpanded
 Precursor to pneumothorax or
pneumomediastinum
Pulmonary Interstitial emphysema (PIE ):
A, CXR shows asymmetric bubblelike,
nonbranching lucencies within the left lung
consistent with PIE. B, The child developed a
tension pneumothorax on subsequent exam.

Pleural disease - Pneumothorax
Pneumothorax:
 Rotation of CXR can obscure a
pneumothorax . Rotation can
also mimic a mediastinal shift.
 A linear shadow of visceral
pleura with lack of lung markings
peripheral to it indicates
collapsed lung
 Flattening or inversion of the
diaphragm on the affected side
 Mediastinal shift toward the
contralateral side
 In erect patients: Pleural gas
collects over the apex .

 In the supine position:
 The juxtacardiac area, the
lateral chest wall, and the
subpulmonic region are the best
areas to search for evidence of
pneumothorax.
 The deep sulcus sign: (very wide
and deep costophrenic angle)
 An ipsilateral increased lucency
in the upper quadrant of the
abdomen.
 Double Diaphragm Sign: both
the diaphragmatic dome and
anterior portions of the
diaphragm are visualized

Double Diaphragm Sign
of Pneumothorax. Air in
the right hemithorax
displaces both the
dome (white arrow)
and the anterior
costophrenic angle
(yellow arrow) in this
patient with a large,
right-sided
pneumothorax. There is
also a deep sulcus sign
present (red arrow).

 large pneumothorax if:
 the vertical distance between
the lung and thoracic cage at
the apex > 3cm
 or the distance between the
lateral lung edge and chest
wall at the level of the hilum
> 2cm
lateral decubitus studies:
 Should be done with the
suspected side up
 The lung will then 'fall' away
from the chest wall
Rib films are indicated
This chest X-ray shows a large
pneumothorax (P) which is >2 cm
depth at the level of the hilum.

 A bulla or thin wall cyst can be
mistaken for loculated
pneumothorax. The pleural
line caused by pneumothorax is
usually bowed at its center
towards lateral chest wall but
the inner margins of bulla or
cyst is generally concave rather
than convex.
 Pneumothorax with pleural
adhesion may simulate bulla or
lung cyst. Differential diagnosis
by comparison with previous
chest radiography, lateral
decubitous or CT scanning
A chest radiograph shows
Right bullous formation

A skin fold can be mistaken for a pneumothorax. Unlike
pneumothorax, skin folds usually continue beyond the chest
wall, and lung markings can be seen beyond the apparent
pleural line.

 Deep sulcus sign (red arrow) in a supine patient in the ICU.
The pneumothorax is subpulmonic.

Hydropneumothorax:
 With the patient
upright, there will be
an air-fluid level in the
thoracic cavity
 On supine radiographs,
a hydropneumothorax
will be more difficult
to see although a
uniform grayness to
the entire hemithorax
with the absence of
vascular markings
suggest the diagnosis

Pleural disease - Pleural thickening
Best seen at the lung edges where the pleura runs tangentially to
the x-ray beam. Causes:
Unilateral pleural thickening:
• Peripheral shadowing on the right
• Loss of right lung volume
• Shadowing over the whole right
lung due to circumferential pleural
thickening
 Benign pleural thickening
 Recurrent inflammation
 Following a pleural empyema
 Complication of haemothorax
 Asbestosis & silicosis
 Recurrent pneumothoraces
 Malignant pleural thickening
 Primary pleural malignancy
• Mesothelioma
• Primary pleural lymphoma
 Pleural metastases
 Secondary pleural lymphoma

Pleural disease - Apical pleural cap
In normal asymptomatic individuals, the apical cap is an irregular
density generally less than 5 mm high located over the apex of the
lung.
Apical pleural cap (yellow arrows)
Causes:
 Pleural thickening/scarring
 Idiopathic: common
feature of advancing age
 Secondary to tuberculosis
 Radiation fibrosis
 Pancoast tumour
 Haematoma
 Lymphoma
 Abscess
 Metastases

Pleural disease - Pleural plaques
Asbestos related pleural plaques:
Calcified pleural plaques with irregular
thickened nodular edges resembling holly
leaf. Costophrenic angles and apices are
spared
 Most pleural plaques are
multiple, bilateral, and often
symmetrical and are located
in the mid-portion of the chest
wall between the seventh and
tenth ribs. they follows rib
contour and diaphragm.
 Plaques may be calcified (they
are irregular, well-defined,
and classically said to look like
holly leaves), however, most
(85-95%) are not
 Visceral pleura, lung apices,
and costophrenic angles are
typically spared.

Pleural disease - Pleural effusion
Pleural effusion is an abnormal
collection of fluid in the pleural space.
Fluid may be (Transudate, Exudate,
Pus, Blood, Chyle, Cholesterol, Urine )
A. Erect frontal Chest X-ray:
1. Blunting of costophrenic angle 
2. Blunting of cardiophrenic angle
3. The diaphragmatic contour is
partially or completely obliterated,
depending on the amount of the
fluid (silhouette sign).
4. Fluid within the horizontal or
oblique fissures
5. Concave meniscus seen laterally and
gently sloping medially (horizontal
in case of hydropneumothorax) 

Pleural effusion - Erect frontal Chest X-ray
6. Massive pleural effusion:
 Opacification of entire hemithorax
(“white-out” lung) and shifting of
mediastinum to the opposite side
(note: The mediastinal shift can be
less prominent or even absent in
the presence of underlying lung
collapse or contralateral
hemithorax abnormality)
 Around 5-7 liters of pleural fluid
 Generally, the pleural effusion is
said to be massive if it crosses the
anterior border of the 2nd rib. It is
said to be moderate if it crosses
the anterior border of the 4nd rib
and is said to be mild or small if it
is below that.
Massive right pleural effusion
(1), with shift of mediastinum
towards left (2)

7. Lamellar effusion:
 linear opacification
paralleling the lateral
aspect of lung.
 It is a shallow collection
between lung surface
and visceral pleural
sometimes sparing the
costophrenic angle.
 It represent interstial
pulmonary fluid.
Chest radiograph showing an encysted pleural
effusion (lenticular shaped opacity) along the
right oblique fissure (asterisk), a right sided
lamellar pleural effusion (arrow), and left
subpulmonic effusion (line)

8. Subpulmonic effusion:
 Unilateral subpulmonary effusion is
more common on right side.
 Left: The distance between the lung
and the stomach bubble will exceed
2 cm (double red arrow)
 Right: appear as a raised diaphragm
with flattening and lateral
displacement of the dome.

9. Loculated (encysted, encapsulated) pleural effusion:
 Loculation secondary to
adhesions after an
infected or hemorrhagic
effusion.
 Peripheral soft-tissue
opacity with smooth
obtuse tapering margins
Pleural opacity.
Encapsulated pleural
effusion – Frontal chest
radiograph; shows a
lenticular opacity with
smooth borders and obtuse
angles (black arrows)

10. Encysted (encapsulated) pleural effusion in the fissure:
 Loculated effusion in the fissures
appears as a well-defined
elliptical opacity with pointed
margins.
 Pseudotumor/vanishing tumor
(phantom tumor): Loculated
effusion in the fissures ,
secondary to congestive heart
failure, hypoalbuminemia, renal
insufficiency or pleuritis.
Radiologically simulating a
neoplasm. It disappears rapidly in
response to the treatment of the
underlying disorder (red arrow)

B. Lateral Chest X-ray:
 Small effusions appear as a
dependent opacity with
posterior upward sloping of
a meniscus-shaped contour.
 The opacity obliterates the
underlying portion of the
diaphragmatic contour
(silhouette sign).
 Can detect an effusion as
small as 50–75 mL
Note the concave meniscus
blunting posterior costophrenic
angle.

C. Supine Chest X-ray:
 Due to the effect of gravity, the
pleural fluid is distributed
throughout the posterior part of
the pleura during supine
position – this cause the
hemithorax to appear whiter or
paler grey compared to the
normal side.
 Vessels are often visible through
the shadowing.
 It is therefore especially difficult
to identify similar sized bilateral
effusions as the density of the
lungs will be similar.
 Requires about 200 ml fluid
Right-sided effusion. a veil-like
increased density of the lower right
hemithorax (blue arrow). Note that the
pulmonary vascular structures are not
obscured or silhouetted by the vague
density but, rather, are still visible
through it (open arrow).

D. lateral decubitus Chest X-ray:
 A small amount of fluid (10-25 mL) can be depicted on this
projection.
 The layering fluid can easily be detected as a dependent, sharply
defined, linear opacity separating the lung from the parietal
pleural and chest wall
 The parietal pleura–chest wall margin can be identified as a line
connecting the inner apices of the curvature of the ribs.
A : There will be lateral
displacement of the
dome of right
hemidiaphragm ( arrow )
B : Right lateral decubitus
view shows the pleural
fluid gravitating to
dependent right pleural
space ( arrows )

Complete white-out of a hemithorax:
 Trachea pulled toward the opacified
side:
 Pneumonectomy
 Total lung collapse 
 Pulmonary agenesis
 Pulmonary hypoplasia
 Trachea remains central in position:
 Consolidation
 Pulmonary oedema/ARDS
 Pleural mass: e.g. mesothelioma
 Chest wall mass: e.g. Ewing sarcoma
 Pushed away from the opacified side:
 Pleural effusion 
 Diaphragmatic hernia
 Large pulmonary mass

How do you determine the etiology of effusion from chest x-ray?
 Bilateral: consider transudative effusions first. You will need
clinical information.
 Bilateral effusions with cardiomegaly: Congestive heart failure
 Bilateral pleural effusions associated with ascites in a alcoholic:
Cirrhosis
 Unilateral: most of them are exudative
 Massive unilateral effusion: Malignancy
 Pleural effusion with apical infiltrates: Tuberculosis
 Pleural effusion with nodes or mass or lytic bone lesions:
Malignancy
 Loculated effusions are empyemas
 Pleural effusion with a missing breast suggesting resection for
cancer: Malignancy
 Pleural effusion following chest trauma: Hemothorax
 In patients with mediastinal lymphoma: Chylothorax

Chest X-ray Abnormalities- Costophrenic angle
Costophrenic (CP) angle blunting:
 On a frontal CXR the costophrenic angles should form acute angles
which are sharp to a point.
 Often the term costophrenic "blunting" is used to refer to the
presence of a pleural effusion. This, however, is not always correct
and costophrenic angle blunting can be related to other pleural
disease, underlying lung disease or Lung hyper-expansion.
1- left CP
angle blunting
in effusion
2- bilateral CP
angles
blunting in
emphysema

Elevated hemidiaphragm: If the left hemidiaphragm is higher
than the right or the right is higher than the left by more than 3 cm
Can result from:
 Above the diaphragm
 Decreased lung volume
 Atelectasis/collapse
 Lobectomy/pneumonectomy
 Diaphragm
 Phrenic nerve palsy
 Diaphragmatic eventration
 Contralateral stroke: usually middle cerebral artery distribution
 Below the diaphragm
 Abdominal tumour, e.g. liver metastases or primary malignancy
 Subphrenic abscess
 Distended stomach or colon
Chest X-ray Abnormalities - Diaphragm

Elevated diaphragm: Can result from:
 Technical
supine position
poor inspiratory effort
 Patient factors
obesity
pregnancy
 Diaphragmatic pathology
bilateral phrenic nerve palsy
pain following abdominal surgery
 Abdominal pathology
mass lesion
massive ascites
 Pulmonic pathology
diffuse pulmonary fibrosis
lymphangitis carcinomatosa
disseminated lupus
erythematosus

Elevated hemidiaphragmElevated diaphragm
 Above the diaphragm
 Decreased lung volume
 Atelectasis/collapse
 Lobectomy/pneumonectomy
 Diaphragm
 Phrenic nerve palsy
 Diaphragmatic eventration
 Contralateral stroke
 Below the diaphragm
 Abdominal tumour, e.g. liver
metastases or primary
malignancy
 Subphrenic abscess
 Distended stomach or colon
 Technical
 supine position
 poor inspiratory effort
 Patient factors
 obesity
 pregnancy
 Diaphragmatic pathology
 bilateral phrenic nerve palsy
 pain following abdominal surgery
 Pulmonic pathology
 diffuse pulmonary fibrosis
 lymphangitis carcinomatosa
 disseminated lupus erythematosus
 Abdominal pathology
 mass lesion
 massive ascites

Diaphragmatic hernia: defect in the diaphragm can result
from:
 Congenital:
 Bochdalek hernia: most common, More frequent on left
side, located posteriorly and usually present in infancy
 Morgagni hernia: smaller, anterior and presents later,
through the sternocostal angles
 Acquired:
 Traumatic diaphragmatic rupture
 Hiatus hernia
 Iatrogenic

Morgagni hernia
are: Anteromedial
parasternal defect,
small, Usually
unilateral, more
often right-sided
(90%)
Bochdalek Hernia : Frontal
view of the chest shows a
large air-containing and
walled structure in the region
of the left lower lobe (white
arrow). It is originating from
below the diaphragm. The air-
containing structure is seen
posteriorly on the lateral view
(red arrow).

Hiatus hernias occur when there is herniation abdominal contents
through the oesophageal hiatus of the diaphragm into the thoracic
cavity. Appears as retrocardiac opacity with air-fluid level
Posteroanterior (PA) and lateral view of hiatal hernia.
Can you see the air-filled "mass" posterior to the heart

Free gas under diaphragm (Pneumoperitoneum): It is a
finding in the chest X-ray seen in case of perforation of
hollow viscus.
CXR shows Minor
opacity in the left
lower zone. Large
volume of free
subdiaphragmatic
gas ( yellow arrow).

Chilaiditi syndrome: is a rare condition in which a portion of the
colon is abnormally located (interposed) in between the liver and the
diaphragm. It is one of the causes of pseudopneumoperitoneum.
 Features that suggest a Chilaiditi syndrome (i.e. Chilaiditi sign):
 Gas between liver and diaphragm
 Rugal folds within the gas suggesting that it is within the bowel.

Cardiophrenic angle lesions:
 The more common:
 Pericardial fat pad
 Pericardial cyst
 Morgagni's hernia
 Lymphadenopathy:
metastases , lymphoma
 Pericardial fat necrosis
 Pericardial lipomatosis
 Other less common:
 Thymoma
 Hydatid cyst
 Right middle lobe collapse
Pericardial
cyst: X-ray
shows a well
circumscribed
mass in
contact with
right cardiac
margin.

Cardiomegaly and heart failure:
The heart is enlarged if the cardiothoracic ratio (CTR) is greater than
50% on a PA view. If the heart is enlarged, check for other signs of
heart failure such as pulmonary oedema, septal lines (or Kerley B
lines), and pleural effusions.
Chest X-ray Abnormalities - Heart
CXR shows:
• Cardiomegaly CTR = 18/30 (>50%)
• Upper zone vessel enlargement (1)
- a sign of pulmonary venous
hypertension
• Pulmonary oedema (2) - bilateral
increased lung markings (classically
peri-hilar and shaped like bats wings
- more widespread in this case)
• Septal (Kerley B) lines (3)
• Pleural effusions (4)

left atrial enlargement:
 The double density sign: Right side of
the dilated left atrium is visible next to
the right heart border (right atrium). It
may extend out beyond the right heart
border, an appearance known as atrial
escape.
 Oblique measurement of greater than
7cm (blue arrow).
 Convex left atrial appendage; produces
“straightening” of the left heart border
- normally it is flat or concave.
 Splaying of the carina to greater than a
90 degree angle (yellow lines).
 Posterior displacement of the left main
stem bronchus on lateral radiographs
resulting to the "walking man" sign.

left atrial enlargement:
 The "walking man" sign: right and left bronchi, therefore, do not overlap,
but rather form an upside down 'V', sometimes referred to as the walking
man sign
 Posterior displacement of a barium-filled esophagus or nasogastric tube
Annotated lateral radiograph shows the markedly dilated left
atrium displacing the left main bronchus posteriorly resulting to the
"walking man" sign

left ventricular enlargement: CXR shows:
 Left heart border is displaced leftward, inferiorly, or posteriorly
 Rounding of the cardiac apex
 The aorta is prominent
 Lateral view: Retrocardiac space become narrowed or disappeared,
esophageal space disappeaered

 If we draw a tangent line from
the apex of the left ventricle to
the aortic knob (red line) and
measure along a perpendicular
to that tangent line (green line)
 The distance between the
tangent and the main
pulmonary artery (between
two small green arrows) falls
in a range between 0 mm
(touching the tangent line) to
as much as 15 mm away from
the tangent line
left heart border:

left heart border abnormalities:
1. The main pulmonary artery may
project beyond the tangent line
(greater than 0 mm). This can occur if
there is increased pressure or
increased flow in the pulmonary
circuit.
2. The main pulmonary artery may
project more than 15 mm away from
the tangent line. This can occur in
left ventricle enlargement and/or
aortic knob enlargement e.g.
atherosclerosis, aortic
incompetence, and mitral
incompetence.

Right atrial enlargement: Features are non-specific but include :
 Right heart enlargement (the right atrium and ventricle cannot be
separately identified on a radiograph) causes filling-in of the
retrosternal clear space and prominence of the right heart border
 A prominently convex lower right heart border
 Enlarged, globular heart
 Narrow vascular pedicle

Right ventricular enlargement: :
 Frontal view demonstrates:
 Rounded left heart border
 Uplifted cardiac apex
CXR showing right
ventricular
hypertrophy (arrows,
note filling of the
retrosternal space by
an enlarged right
ventricle in the lateral
view) and enlarged
central pulmonary
arteries (arrowhead).
 Lateral view demonstrates:
 Filling of the retrosternal
space
 Rotation of the heart
posteriorly

Pulmonary embolism (PE): Features include:
 Normal CXR
 Plate atelectasis
 Hampton hump: pleural-based
opacity (pulmonary infarction)
 Small pleural effusion
 Elevated hemidiaphragm
 Fleischner’s sign (prominent
amputated pulmonary artery)
 Westermark’s sign (peripheral
oligaemia)
 Palla's sign: Enlarged right descending pulmonary artery
 The more abnormal the CXR, the less likely is Pulmonary embolism
Normal CXR in a breathless hypoxic person in the absence of
bronchospasm means that Pulmonary embolism is likely

Heart- Pulmonary embolism
A chest radiograph shows a
Westermark sign (arrow), with a
focal area of oligemia in the right
middle zone and cutoff of the
pulmonary artery in the upper
lobe of the right lung.
Fleischner sign: Refers to the
prominence of central pulmonary
artery caused either by pulmonary
hypertension that develops secondary
to PE or by distension of the vessel by
a large clot

Pulmonary Arterial Hypertension: Features include:
 Elevated cardiac apex due to right ventricular hypertrophy
 Enlarged right atrium
 Prominent pulmonary outflow tract
 Enlarged pulmonary arteries
 Pruning of peripheral pulmonary vessels

Ventricular aneurysm:
 A ventricular aneurysm is usually the sequel to a myocardial
infarct, thus cases of calcified ventricular aneurysm are
rare.
 Typically the left cardiac border changes shape and bulges.

Ventricular
Pseudoaneurysm:
 It is caused by a
contained
rupture of the LV
free wall.
 A chest
radiograph may
show
cardiomegaly
with an abnormal
bulge on the
cardiac border.

Pericardial effusion:
 It occurs when excess fluid collects in
the pericardial space (a normal
pericardial sac contains approximately
30-50 mL of fluid).
 CXR Suggestive but not usually
diagnostic.
 Globular enlargement of the cardiac
shadow giving a water bottle
configuration
 Widening of the subcarinal angle
without other evidence of left atrial
enlargement may be an indirect clue

Pericardial effusion:
 lateral CXR may show:
 Loss of retrosternal clear space
 A vertical opaque line
Produced by pericardial fluid
(yellow arrows) separating a
vertical lucent line directly
behind sternum Produced by
epicardial fat (white arrows)
anteriorly from a similar lucent
vertical lucent line Produced by
pericardial fat (red arrows)
posteriorly; this is known as
the Oreo cookie sign
Real
Oreo
cookies

Transposition of the great arteries (TGA) (also known as transposition
of the great vessels (TGV)):
 The classic appearance described as an egg on a string sign
 Most common cyanotic congenital heart lesion
 The aorta arises from the morphologic right ventricle and the
pulmonary artery arises from the morphologic left ventricle
 Narrowing of the superior mediastinum on radiographs
 Patent ASD, VSD, Foramen ovale, systemic collaterals to sustain life
 The right atrial border is convex, and the left atrium is enlarged
CXR Abnormalities - Congenital heart disease

Total Anomalous Pulmonary Venous Return:
 Occurs when the pulmonary veins fail to drain into the left atrium
and instead form an aberrant connection with some other
cardiovascular structure
 2% of cardiac malformations
 SNOWMAN SIGN: resembles a snowman

Partial Anomalous Pulmonary Venous Return:
Scimitar syndrome
 Anomalous pulmonary vein drains any or all of the lobes of the
right lung, and empties into the inferior vena cava, portal vein,
hepatic vein, or right atrium
 Vein appears like a scimitar, a sword with a curved blade that
traditionally was used by Persian and Turkish warriors.
 Hypoplasia of right lung, hypoplasia of right pulmonary artery, and
anomalous arterial supply of the right lower lobe from abdominal
aorta.

Tetralogy of Fallot:
 10%–11% of cases of congenital heart disease
 Components: Ventricular septal defect, Infundibular pulmonary
stenosis, Overriding aorta, Right ventricular hypertrophy
 Blood flow to the lungs is usually reduced
 The heart has the shape of a wooden shoe or boot (in French,
coeur en sabot)

Aortic Coarctation:
 5%–10% of congenital cardiac lesions
 Eccentric narrowing of the lumen of aorta at the level where the
ductus or ligamentum arteriosus inserts anteromedially
 Classic radiologic signs:
 Figure of 3 sign: contour abnormality of the aorta
 Reverse figure of three sign is observed on the left anterior
oblique view during barium esophagography
 Inferior rib notching: Roesler sign on CXR pathognomonic
Left anterior oblique view

Mediastinal abnormalities - Mediastinal widening
Superior mediastinum:
 Should have a width less than 8 cm
on a PA CXR.
 A widened mediastinum can be
associated with:
 Anteroposterior CXR view
 Unfolded aortic arch
(not pathological) or a thoracic
aortic aneurysm
 Mediastinal masses
 Oesophageal dilatation
 Ruptured aorta
 Mediastinal lipomatosis:
increased deposition of normal
unencapsulated fat
Unfolded aorta: widened and
'opened up' appearance of
the aortic arch. It is seen with
increasing age

Mediastinal abnormalities - Aortic Dissection
Aortic Dissection: CXR
findings include:
1. Mediastinal widening; it is
noted in 60% of patients
2. Irregularity of the aortic
contour
3. Double aortic contour
4. Double-calcium sign:
Inward displacement of
atherosclerotic calcification
by more than 10 mm
5. Pleural effusion (more
common on the left side;
suggests leakage)
CXR shows; double density
aortic arch (yellow/red arrows),
Mediastinal widening, and
Cardiac enlargement

Mediastinal abnormalities - Aortic Dissection
6. Tracheal displacement
to the right
7. Pericardial effusion
8. Cardiac enlargement
9. Displacement of a
nasogastric tube
10. Left apical pleural
capping (opacity) due to
secondary mediastinal
hematoma
11. Normal CXR in 12% of
patients
Aortic Dissection: rightward deviation of the
trachea (red arrow); left apical pleural capping
(blue arrow); aortic “double-calcium” sign
(between white arrows); depression of the left
bronchus (purple arrow); pleural effusion
(green arrow); widened mediastinum and loss
of the aorto-pulmonary window (not labeled).

Mediastinal abnormalities - Pneumomediastinum
Radiographic features of Pneumomediastinum:
Small amounts of air appear as linear or curvilinear lucencies outlining
mediastinal contours and form:
1. Pneumoprecardium: where air enters the pericardial cavity
2. Subcutaneous emphysema
Pneumo-precardium. Plain posterior-anterior (PA)
and lateral chest radiograph shows the presence
of air (arrow) between the pleura and left border
(PA) and anterior (lateral) of the heart
subcutaneous emphysema

3. air around pulmonary artery and main branches: ring around
artery sign
4. air outlining major aortic branches: tubular artery sign
Tubular Artery Sign (Red arrows)
Ring around artery sign

5. Continuous diaphragm sign: due to air trapped posterior to
pericardium
6. Spinnaker Sail Sign (angel wing sign) is seen on neonatal
postero-anterior CXR when thymic lobes are displaced laterally
by air, (Very typical sign in neonatal age).
Spinnaker Sail Sign (angel wing sign)
Continuous diaphragm sign

 Naclerio V sign:
It is seen as a V-shaped air collection. One limb of the V is produced
by mediastinal air outlining the left lower lateral
mediastinal border. The other limb is produced by air between the
parietal pleura and medial left hemidiaphragm.
Lateral Chest X-Ray
Retrosternal air
Lateral Decubitus Chest X-Ray
Air will not move with change in position
Neck Films
Air outlining fascial planes of the neck
Naclerio V sign

Mediastinal abnormalities - Masses
Clues to locate mass to mediastinum
Masses in the lungMediastinal masses
 May contain air
bronchograms
 A lung mass abutts
the mediastinal
surface and creates
with lung an acute
angles.
 Not contain air bronchograms
 The margins with the lung will be obtuse.
 Mediastinal lines (azygoesophageal recess,
anterior and posterior junction lines) will be
disrupted.
 There can be associated spinal, costal or
sternal abnormalities.
LEFT: A lung mass abutts the
mediastinal surface and creates
acute angles with the lung.
RIGHT: A mediastinal mass will
sit in the mediastinum, creating
obtuse angles with the lung.

Clues to locate mass to mediastinum:
LEFT: there is a lesion that has an acute border
with the mediastinum. This must be a lung mass.
RIGHT: shows a lesion with an obtuse angle to the
mediastinum. This must be a mediastinal mass.
Localize mass within the mediastinum
In lateral CXR, mediastinum is divided into superior and Inferior.
Inferior mediastinum is divided into anterior, middle, and posterior

Anterior Mediastinal Masses (5Ts)
 Thymus Abnormalities (thymoma, invasive thymoma, thymic carcinoma,
thymolipoma/thymoliposarcoma, thymic cyst, thymic hyperplasia, thymic
carcinoid)
 Thyroid (thyroid neoplasms, thyroid goiter)
 Terrible Mediastinal Lymphoma (Hodgkin and non-Hodgkin lymphoma)
 Germ Cell Tumors (Teratoma, teratocarcinoma, seminoma, choriocarcinoma,
embryonal cell carcinoma, endodermal sinus tumors (yolk sac tumors))
 Thoracic Aortic Aneurysm
 Pericardial Cyst
 Morgagni Hernia
 Sternal Tumors
 Pericardial Fat Pad
B-cell lymphoma. (A) a very large
mass (arrows). (B) The mass in the
anterior mediastinum (outlined in
yellow) is displacing the trachea
(blue lines) posteriorly.

Chest x ray-fundamentals

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