Basic approach to chest X-ray interpretation

Lecture 6 Dr. Kosar kamal ahmed

HD diagnostic radiology

Courtesy of :

• Prof. Dr. mamdouh mahfouz

• Radiology assistant ( chest radiology basic interpretation , chest

radiology lung diseases )

Let’s go back to where we skipped

• Technical adequacy

• Cardiothoracic ratio + CP angles

• Mediastinal contour and para vertebral lines

• Lung zones

• Hidden areas

• Bony stuctures

Azygo-esophageal line

Rt. Paratracheal stripe

Let’s go back to where we skipped

• Technical adequacy

• Cardiothoracic ratio + CP angles

• Mediastinal contour and para

vertebral lines

• Lung zones

• Hidden areas

• Bony stuctures

Lung zones

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Lung zonestry to pic pathology

Pattern approach On a chest x-ray : • lung abnormalities will either present as areas of

– increased density or as areas of decreased density.

• Lung abnormalities with an increased density also called opacities are the

most common.

• A practical approach is to divide these into four patterns:– 1. Consolidation ( + opacity of without air bronchogram )

– 2. Interstitial infiltration

– 3. Nodules or masses

– 4. cavitary lesion

Important points to keep in mind

• You have to realize that it is not always possible to divide lung abnormalities

into one of these four patterns .

• Sometimes you are confronted with an abnormality that looks like a mass, but

it could also be a consolidation.– Just do the workup of both the differential diagnosis of masses and consolidation.

– In such a case information from clinical data, old films or follow up films and CT scan will

usually solve the problem.

• Finally in some cases only biopsy will provide a diagnosis .

Consolidations

• They can be small or large

• Focal or multifocal

• Central or peripheral

According to the pathogenesis

Consolidation • Consolidation is the result of

replacement of air in the alveoli by

transudate, pus, blood, cells or other

substances.

• Pneumonia is by far the most

common cause of consolidation.

• The disease usually starts within the

alveoli and spreads from one alveolus

to another.

• When it reaches a fissure the spread

stops there .

Consolidation

• The keyfindings on the X ray

are :

1. ill defined , homogeneous

opacity obscuring vessels

2. Silhouette sign: loss of lung/soft

tissue interface

3. Air bronchogram

4. Extension to the pleura or

fissure, but not crossing it

5. No volume loss .

Consolidation We may think of consolidation according to it’s

contents

Consolidation Or We may think of consolidation according to pattern of distribution

Consolidation An other way to approach consolidation is by

chronicity

Consolidation • It is very important to differentiate between acute consolidation and chronic

consolidation, because it will limit the differential diagnosis.

In chronic consolidation we think of :

i. Neoplasm with lobar or segmental post-obstructive pneumonia.

ii. Lung neoplasms like bronchoalveolar carcinoma and lymphoma.

iii. Chronic post-infection diseases like organizing pneumonia (OP) or chronic

eosinophilic pneumonia, which both present with multiple peripheral

consolidations.

iv. Sarcoidosis is the great mimicker and sometimes the granulomatous noduli

are so small and diffuse that they can present as consolidation ,This is

known as alveolar sarcoidosis .

v. Alveolar proteinosis is a rare chronic disease that is characterized by filling

of the alveoli with proteinaceous material.

Consolidation

• The most common presentation of consolidation is lobar or segmental.

The most common diagnosis is lobar pneumonia.

Lobar consolidation

• increased density with ill defined borders in the left lung• the heart silhouette is still visible, which means that the density is in the

lower lobe• Air bronchogram

Spine sign +ve

Lobar consolidation

• In consolidation there should be

no or only minimal volume loss,

which differentiates consolidation

from atelectasis.

• Expansion of a consolidated lobe

is not so common and is seen in

Klebsiella pneumoniae and

sometimes in Streptococcus

pneumoniae, TB and lung cancer

with obstructive pneumonia.

Lobar consolidation• Based on the images alone, it is usually not possible to determine the cause of the consolidation.

• Other things need to be considered, like acute or chronic illness, clinical data and other non pulmonary

findings.

• Here we have a number of xrays with consolidation ; Notice the similarity between these chest x rays

Lobar pneumonia in a patient with cough and feverPulmonary hemorrhage in a patient with hemorrhage Organizing pneumonia (OP) multiple chronic consolidationsInfarction : peripheral consolidation in a patient with acute shortness of breath with low oxygen level and high D-dimer

Lobar consolidation• Based on the images alone, it is usually not possible to determine the cause of the consolidation.

• Other things need to be considered, like acute or chronic illness, clinical data and other non pulmonary

findings.

• Here we have a number of xrays with consolidation ; Notice the similarity between these chest x rays

Pumonary cardiogenic edema filling of the alveoli with transudate in a patient with congestive heart failure. Sarcoidosis : at first glance this looks like consolidation, but in fact this is nodular interstitial lung disease, that is so widespread that it looks like consolidation .

Diffuse consolidation

• The most common cause of diffuse consolidation is pulmonary edema due to heart

failure.

Diffuse consolidation

• bilateral perihilar consolidation with air bronchograms and ill defined borders

• an increased heart size

• subtle interstitial markings

• probably a large vascular pedicle.

Bat wing shadowing

Is it possible for a patient to have pulmonary edema with a normal cardiac size ?

Diffuse consolidation

• Unlike lobar pneumonia, which starts in the alveoli, bronchopneumonia starts in the airways as acute

bronchitis.

• It will lead to multifocal ill defined densities.

• When it progresses it can produce diffuse consolidation.

• The disease does not cross the fissures, but usually starts in multiple segments.

• Bronchopneumonia can be caused by many microorganisms.

• This proved to be legionella pneumonia

This patient had fever and cough

Diffuse consolidation

• The chest x ray shows diffuse consolidation with 'white out' of the left lung with an airbronchogram.

• This patient had a chronic disease with progressive consolidation.

• The disease started as a persitent consolidation in the left lung and finally spread to the right lung.

Bronchoalveolar carcinoma

An other approach is to notice pattern of distribution

Batwing Vs. reversed batwing

• A bilateral perihilar distribution of

consolidation is also called a

Batwing distribution.

• The sparing of the periphery of the

lung is attributed to a better

lymphatic drainage in this area.

• It is most typical of pulmonary

edema, both cardiogenic and

noncardiogenic.

• Sometimes it is seen in

pneumonias

• Peripheral or subpleural

consolidation is called reverse

Batwing distribution.

• It is frequently seen in chronic

lung disease .

Batwing Vs. reversed batwing

• Multifocal consolidations are also described as

multifocal ill defined opacities or densities.

• In most cases these are the result of airspace

consolidations due to bronchopneumonia.

• Bronchopneumonia starts in the bronchi and then

spreads into the lung parenchyma.

• This can lead to segmental, diffuse or multifocal ill

defined densities.

• In some cases however the underlying pathology of

multiple ill defined densities is interstitial disease , like

in the alveolar form of sarcoidosis in which the

granulomas are very small and fill up the alveoli .

Multifocal ill defined consolidations ( opacities )

This patient had a several month history of chronic nonproductivecough, that did not respond to antibiotics

• Probably we are dealing with multifocal consolidations

• but one might also consider the possibility of multiple ill defined masses

• Biopsy revealed the diagnosis of organizing pneumonia (OP)

Summary : acute focal consolidation can be

pneumonia or infarction

Pneumonia Infarction

Cough , fever P l e u r i t i c c h e s t p a i n a n d h a e m o p t a s i s

Pulmonary nodules and masses

• A well defined opacity that is < 3 cm on a CXR is a nodule

• A well defined opacity that is > 3 cm in a CXR is a mass

Pulmonary nodulesDDx

What are the common ones ?

Pulmonary nodules

Pulmonary nodule how to assess ?

Well defined edge Vs. spiculated edge

Pulmonary nodule how to asses ?

• Number : multiple nodules are usually metastatic or less likely H. cysts

• A well defined edge is usually on the benign while spiculated edge is

malignant

• Presence of calcification or especially pop corn calcification is benign .

• Density : usually assessed by CT – Fat --- pathognomonic for hamartoma

– Fluid --- H. cyst

– Soft tissue --- metastasis or primary carcinoma

• Vascular pedicle ---- AVM

But !!

Some nodules can be indeterminate and need CT or FNA for further evaluation

Pulmonary masses

Pulmonary masses

• Any pulmonary mass in an adult is carcinoma until proved otherwise

• Presence of calcification is benign in nodule while not in mass

• Multiplicity of the masses can be metastases or multiple hydatids

How to differentiate multiple pulmonary masses from multiple pulmonary metastases ?

• There are three signs that make

the diagnosis of H. possible by

CXR :

1. Extreme sharp margin

2. Air in the wall ( halo sign )

3. Air / fluid level ( water lilly

sign )

Cavitary lesions

• A cavity is defined as a ‘gas-filled space,

seen as a lucency or low attenuation area .

• The cavity is usually the result of the

expulsion or drainage of a necrotic part of

the lesion via the bronchial tree.

• Although air–fluid levels may be seen in

cavitations, the term is not synonymous with

abscess .

Cavitary lesions

Cavitary lesions

• Thick walled cavity

• Containing air alone

• Internal surface of the cavity – Smooth – chronic abscess

– Irregular – malignant ( cavitating :

primary /secondary mass )

Cavitary lesions

• Thick walled cavity

• Containing air / fluid level

• Look for the surface of the fluid

level : – Regular ( linear ) – chronic

abscess

– Irregular ( undulating ) – ruptured

hydatid cyst

Cavitary lesionsabscess

Cavitary lesionshyatid cyst

• Only three signs are

dependable in CT to diagnose

H. cyst :

– Floating shadows within the

cyst

– Calcification in the wall

– Daughter cysts

Cavitary lesions

• Thick walled cavity

• Containing air + mass

• They can be : – Fungal ball ( mycetoma )

– Ruptured hydatid

– Necrotic tumor

– Blood clot

Cavitary lesions

• Thin walled cavity

• Containing air

• Look for the location of the

cavity : – Central ( in lung parenchyma ) –

pneumatocele – Peripheral ( sub-pleural) –

emphysematous bulla

Cavitary lesions

End of part two

Thank you for your attention