Maciej Jędrzejczyk MD, PhD

Department of Diagnostic Imaging,

2nd Division of Warsaw Medical Univeristy

Introduction to chest radiology

Chest X-ray anatomy

A litle bit of CT and PET

Common general findings

Common pathologies

US – is it useful?

Summary

Imaging methods

- Chest X-Ray (CXR) - Computed Tomography (CT)

- Ultrasound (US) - Scintygraphy (SC) - Positron Emission Tompgraphy (PET) - Magnetic Resonance (MR)

David A. Lisle „Imaging for students”

4th Edition (2012)

www.radiologyassistant.nl

Density:

- Air

- Fat

- Soft tissue

- Bone

How to do it?

Stator

Rotor

Anode (+)

Cathode (-)

Symetrical and stright localization

of clavicular heads

and spinous processes are

demonstrating a diagnostic

image.

How to do it – patient positioning

How to do it – patient positioning

The patient should be examined at the moment of full inspiration (holding breath). The diaphragm contour should be at the level of the 8th to 10th rib (posterior part ) or 5th to 6th (anterior part).

Negative or positive

Parameter settings:

- high mA to reduce exposure time

- high mA, low kVp for high image contrast

- high kVp for increased photon penetration

NEGATIVE POSITIVE OVERP. UNDERP.

Chest anatomy A-P projection

- Respiratory tract

- Gastrointestinal tract

- Heart and vessels

- Bones

- Muscles

- Others

On the PA chest-film it is important

to examine all the areas where the

lung borders the diaphragm, the

heart and other mediastinal

structures.

These lines and silhouettes are

useful localizers of disease,

because they can be displaced or

obscured with loss of the normal

silhouette.

On a chest film only the outer contours of the heart

are seen.

However it can be helpful to know where the different

compartments are situated.

Left Atrium

Most posterior structure.

Left atrial appendage (in purple) can sometimes be

seen as a small outpouching just below the

pulmonary trunk.

Right Atrium

Receives blood from the inferior and superior vena

cava.

Left Ventricle

Situated to the left and posteriorly to the right

ventricle.

Right Ventricle

Most anterior structure and is situated behind the

sternum.

Chest anatomy lateral projection

Chest anatomy lateral projection

On a normal lateral view the contours of the heart are visible

and the IVC is seen entering the right atrium.

The retrosternal space should be radiolucent.

As you go from superior to inferior over the vertebral bodies they

should get darker,.

The contours of the left and right diaphragm should be visible.

However the left diaphragm can only be seen to a point where it

borders the heart .

Chest anatomy lateral projection

Left Atrium

The upper posterior border of the

heart is formed by the left atrium.

Left Ventricle

Forms the lower posterior border.

Right Ventricle

The lower retrosternal space is

filled by the right ventricle.

Heart dimension (HD<1/2ThD)

The left pulmonary artery runs over the left main

bronchus, while the right one runs in front of the right

main bronchus.

Hence the left hilum is higher than the right.

Both pulmonary arteries and veins can be identified on

a lateral view and should not be mistaken for

lymphadenopathy.

The lower lobe pulmonary arteries extend inferiorly from

the hilum.

They are described as little fingers, because each has

the size of a little finger.

Pulmonary vesels

The mediastinum can be divided into an anterior,

middle and posterior compartment, each with it's

own pathology.

Mediastinal lines

Mediastinal lines or stripes are interfaces

between the soft tissue of mediastinal structures

and the lung.

Displacement of these lines is helpful in finding

mediastinal pathology.

Mediastinum

Superior and inferior

mediastinum

Mediastinum

Hiatal hernia

Mediastinum enlargment

Mediastinum - enlargement

Lympadenopathy - PET

Hilar enlargement

Enlargement of the hili is usually due

to lymphadenopathy or enlarged

vessels.

1. Lymphadenopathy and groundglass

appearance of the lungs.

2. Bilatral lymphadenopathy.

3. Bulky lymphadenopathy.

4. 1-2-3 sign.

5. Nodular lung pattern, no

lymphadenopathy.

6. Hilar and paratracheal

lymphadenopathy.

Hilar enlargement

Lung fissures

Lung fissures

The right lung lobes

The right lung lobes

The right lung lobes

The left lung lobes

The left lung lobes

Bones – how to count the ribs?

What is important?

What is important?

Stuctures – leadpoints:

- heart position,

- contour of diagphragms,

- liver shadow,

- gas bubbles,

- hila positions,

- aorta contour.

How to read it?

How to read it?

Lung parenchyma

What is important?

Hidden areas

There are some areas that need

special attention, because pathology

in these localizations can easily be

overlooked:

- apical zones

- hilar zones

- retrocardial zone

- zone below the dome of diaphragm

These areas are also known as the

hidden areas.

Here is an example of

a large lesion in the

right lower lobe, which

is difficult to detect on

the PA-film, unless

when you give special

attention to the

hidden areas.

Notice the subtle

increased density in the

area behind the heart

that needs special

attention (red arrow).

This was a lower lobe

pneumonia.

Anatomical variant

Vena azygos lobe

A common normal variant is the

azygos lobe.

The azygos lobe is created when

a laterally displaced azygos vein

makes a deep fissure in the upper

part of the lung.

On a chest film it is seen as a fine

line that crosses the apex of the

right lung.

Anatomical variant?

Technique

mAs

kVp

slice thickness

(beam collimation)

pitch (table speed per

gantry rotation/beam

collimation)

Native CT

Contrast enhanced CT

CT angiography

Perfusion imaging

HRCT

Reconstructions

Pilot

Windows

CE-CT anatomy

Planar reconstructions

HRCT – special technique

dedicated to lung diseases

- narrow slice width is used (usually <1 mm)

- high spatial resolution image

reconstructions algorithms are implemented

- minimized filed of view (not necessery in

modern CT-machines)

- mAs elevated to reduce noise signals

(radiation dose is elevated as well!).

Secondary lobule is the basic anatomic and fuctional

unit of pulmonary structure.

It is the smallest lung unit surrounded by connective

tissue septa and is made up of few pulmonary acini,

that contain the alveoli.

The secondary lobule is supplied by terminal bronchiole

in the center, that is parallelled by the centrilobular

artery.

Pulmonary veins and lymphatics run in the periphery of

the lobule within the interlobular septa.

Centrilobular area is the central part of the secundary

lobule.

It is usually the site of diseases, that enter the lung

through the airways ( i.e. hypersensitivity pneumonitis,

respiratory bronchiolitis, centrilobular emphysema ).

Perilymphatic areas the peripheral part of the

secundary lobule.

It is usually the site of diseases, that are located in the

lymphatics of in the interlobular septa ( i.e. sarcoid,

lymphangitic carcinomatosis, pulmonary edema).

Focal septal thickening in lymphangitic

carcinomatosis and small nodular lesions

(metastasis).

PET = radiology + nuclear medicine

PET – characterization of lesion (ca within

atelectasis).

PET-CT can detect malignancy in

focal pulmonary lesions of

greater than 1 cm with

sensitivity of about 97% and

specificity of 78%.

False-positive findings in the

lung are seen in granulomatous

disease and rheumatoid

disease.

False negatives are seen in low

grade malignant tumors like

carcinoid and alveolar cell

carcinoma and lesions of less

than 1 cm.

PET – monitoring therapy

Lung abnormalities mostly present as

areas of increased density, which can

be divided into the following patterns:

- consolidation,

- atelectasis,

- nodule or mass,

-interstitial changes.

Less frequently areas of decreased

density are seen as in emphysema or

lung cysts.

Consolidation Consolidation is the result of replacement of air in the

alveoli by transudate, pus, blood, cells or other

substances.

The key-findings on the X-ray are:

•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 lung volume loss.

Form of consolidation - pattern of distribution:

•diffuse - perihilar (batwing) or peripheral (reversed

batwing),

•lobar or focal.

•multiple - usually multiple ill-defined densities.

Consolidation

Consolidation One must differentiate between acute

consolidation and chronic consolidation!

In chronic disease we think of:

• neoplasm with lobar or segmental post-

obstructive pneumonia,

• chronic post-infection diseases like

organizing pneumonia (OP) or chronic

eosinophilic pneumonia, which both present

with multiple peripheral consolidations,

• in sarcoidosis sometimes the

granulomatous noduli are so small and

diffuse that they can present as

consolidation (veolar sarcoidosis).

Consolidation

Consolidation

Batwing

- bilateral perihilar distribution of

consolidation.

The sparing of the periphery of the lung is

attributed to a better lymphatic drainage in

this area.

It is most typical for pulmonary edema, both

cardiogenic and non-cardiogenic.

Sometimes it is seen in pneumonias.

Reverse Batwing

- peripheral or subpleural consolidation.

It is frequently seen in chronic lung disease.

Consolidation

Silhuette sign

This is a very important sign. It enables us

to find subtle pathology and to locate it

within the chest.

The loss of the normal silhouette of a

structure is called the silhouette sign.

ARDS – diffuse consolidations

(periferal distribution).

Increased lung attenuation is called ground-glass-

opacity (GGO) - hazy increase in lung opacity

without obscuration of underlying vessels.

We deal with consolidation if the increase in lung

opacity obscures the vessels.

In both ground glass and consolidation the

increase in lung density is the result of

replacement of air in the alveoli by fluid, cells or

fibrosis.

In GGO the density of the intrabronchial air

appears darker as the air in the surrounding

alveoli.

This is called the 'dark bronchus' sign

In consolidation, there is exclusively air left

intrabronchial.

This is called the 'air bronchogram'.

Ground-glass opacity

- Is due to filling of the alveolar spaces with pus,

edema, hemorrhage, inflammation or tumor cells.

- as well as thickening of the interstitium or

alveolar walls below the spatial resolution of the

HRCT as seen in fibrosis.

So it either be the result of air space disease

(filling of the alveoli) or interstitial lung disease

(i.e. fibrosis).

The location of the abnormalities in ground glass

pattern can be helpfull:

- upper zone predominance: respiratory

bronchiolitis, PCP.

- lower zone predominance: UIP, NSIP, DIP.

- centrilobular distribution: hypersensitivity

pneumonitis, respiratory bronchiolitis

Treatable or not treatable?

Ground-glass opacity is nonspecific,

but highly significant finding since 60-80% of

patients with ground-glass opacity on HRCT have

an active and potentially treatable lung disease.

In the other 20-40% of the cases the lung disease

is not treatable and the ground-glass pattern is the

result of fibrosis.

Low Attenuation pattern

Abnormalities that result in decreased

lung attenuation or air-filled lesions:

- emphysema,

- lung cysts (LAM, LIP, Langerhans cell

histiocytosis),

- bronchiectasis,

- honeycombing.

Most diseases with a low attenuation

pattern can be readily distinguished on

the basis of HRCT findings.

Low Attenuation pattern

Upper lung zone preference is seen in:

- inhaled particles: pneumoconiosis (silica

or coal),

- smoking related diseases (centrilobular

emphysema,

- respiratory bronchiolitis (RB-ILD),

- langerhans cell histiocytosis,

- hypersensitivity pneumonitis,

- sarcoidosis.

Lower zone preference is seen in:

- UIP

- aspiration

- pulmonary edema

Central distribution is seen in sarcoidosis and

cardiogenic pulmonary edema.

Peripheral distribution is mainly seen in

cryptogenic organizing pneumonia (COP),

chronic eosinophilic pneumonia and UIP.

Low Attenuation pattern

Emphysema typically presents as areas of

low attenuation without visible walls as a

result of parenchymal destruction.

Centrilobular emphysema - most common

type with irreversible destruction of

alveolar walls in the centrilobular portion of

the lobule (associated with smoking).

Panlobular emphysema - affects the whole

secondary lobule with lower lobe

predominance (alpha-1-antitrypsin

deficiency, and long-last smokers).

Paraseptal emphysema - adjacent to the

pleura and interlobar fissures - isolated

phenomenon in young adults, or in older

patients with centrilobular emphysema.

Interstitial

Interstitial

Interstitial

Interstitial edema usually presents as

reticulation.

A typica l sign are Kerley’s B lines:

1-2 cm long horizontal lines near the

lateral pleura.

The main differential diagnosis of

Kerley B lines is:

- interstitial edema in heart failure,

- lymphangitis carcinomatosa.

Interstitial Most of our knowledge about imaging findings in interstitial lung

disease comes from HRCT.

On HRCT there are four patterns: reticular, nodular, high and low

attenuation.

On a Chest X-Ray it can be very difficult to determine whether there

is interstitial lung disease and what kind of pattern we are dealing

with.

On a CXR the most common pattern is reticular.

The ground-glass pattern is frequently not detected on a chest x-

ray.

The cystic pattern is also difficult to appreciate on a cest x-ray.

When the cysts have thick walls like in Langerhans cell histiocytosis

or honeycombing, it frequently presents as a reticular pattern on a

CXR.

Usual interstitial pneumonia (UIP)

is a form of lung disease characterized

by progressive scarring of both lungs.

Pneumocystis jvr. pneumonia (PCP).

Nodular vs reticular changes.

Atelectasis Atelectasis = lung-collapse

-is the result of loss of air in a lung or part

of the lung with subsequent volume loss

due to airway obstruction or compression

of the lung by pleural fluid or

a pneumothorax.

In many cases atelectasis is the first sign

of a lung cancer!

The key-findings on the CRX are:

• sharply-defined opacity obscuring vessels

without air-bronchogram,

• volume loss resulting in displacement of

diafragm, fissures, hili or mediastinum

Atelectasis Lobar atelectasis

-is an important finding on a chest x-

ray and has a limited differential

diagnosis.

The most common causes of

atelectasis are:

• bronchial carcinoma in smokers,

• mucus plug in patients on

mechanical

ventilation or astmathics (ABPA),

• malpositioned endotracheal tube,

• foreign body in children.

Sometimes lobar atelectasis produces

only mild volume loss due to

overinflation of the other lungparts!

Atelectasis

Right middle lobe atelectasis

Findings:

• blurring of the right heart border

(silhouette sign)

• triangular density on the lateral view

as a result of collapse of the middle

lobe

• usually right middle lobe atelectasis

does not result in noticable elevation

of the right diaphragm.

Atelectasis of RUL

Total atelectasis

Tatelectasis of the right lung due to mucus plugging.

Notice the displacement of the mediastinum to the

right.

Re-aeration on follow-up chest film after treatment

with a suction catheter.

The mediastinum has regained its normal position.

Nodule

Solitary Pulmonary Nodule (SPN) A SPN is defined as a discrete, well-marginated,

rounded opacity less than or equal to 3 cm in

diameter.

It has to be completely surrounded by lung

parenchyma, does not touch the hilum or

mediastinum and is not associated with

adenopathy, atelectasis or pleural effusion.

The differential diagnosis of SPN is basically the

same as of a mass except that the chance of

malignancy increases with the size of the lesion.

Lesions smaller than 3 cm, i.e. SPN's are most

commonly benign granulomas, while lesions

larger than 3 cm are treated as mlignancies.

Nodule

Fleischner Society recommendations for follow-up of nodules

Previous chest radiographs should be reviewed to determine if the lesion has been stable

over 2 years.

If so, no further follow up is necessary, with the exception of pure ground-glass lesions on CT

scans, which can be slower growing.

For lesions with a benign pattern of calcification, further testing is not necessary.

Management of indeterminate lesions greater than 8-10 mm depends on clinical probability of

malignancy, as follows:

Low probability: Serial CT scanning at 3, 6, 12, and 24 months

Intermediate probability: PET-CT, contrast-enhanced CT, transthoracic needle aspiration and/or

transbronchial needle aspiration (TBNA)

High probability: Surgical resection

Any unequivocal growth noted during follow up means that a definitive tissue diagnosis is needed.

Nodule – sign of malignancy

Nodule – sign of malignancy

- Size:

4 - 7mm – 0,9%,

8 – 20mm – 18%,

>20mm – 50%,

>30mm – 75-80%.

- Bronchogram seen- 65% malignant. - Wall thickness (>15 mm), irregular cavitation– 90%. - Contrast enhancement:

>20jH – mal.

<15jH – ben.

- Volume Doubling Time (VDT) - malignant 30-400 days

Multiple lesions Multiple masses

The differential diagnostic list of multiple masses is very

long.

Metastases

Metastases are the most common cause of multiple

pulmonary masses.

Usually they vary in size and are well-defined.

They predominate in the lower lobes and in the

subpleural region.

HRCT will demonstrate the random distribution unlike

other diseases that have a perilymphatic or

centrilobular distribution.

Multiple nodules

Multiple nodules - miliary

Cancer 1. Hilar 2. Nodule 3. Cavity 4. Subpleural 5. Obturative 6. Atelectasis 7. Bronchiectasis 8. Pleural effusion 9. Tumor necrosis 10. Atelectasis and abscess 11. Obturative emphysema 12. Infiltration of mediastinum 13. Pancoast tumor 14. Lymph node involvement 15. Carina infiltration 16. Pericardial infiltration

Cancer

Cancer

Sign of benignity

- large calcifications,

- smooth margins,

- fat,

- spontaneous regression,

- long VDT or stablility over time

Lines and tubes

Lines and tubes and others: endotracheal tube

Lines and tubes and others: peace maker

Heart valves:

- green: pulmonic v.

- blue: aortic v.

- pink: mitral v.

- yellow: tricuspid v.

Heart valves – artificial heart

Heart valves – mitral

Pneumothorax - accumulation of air in the pleural space.

Radiological signs:

Collapse/distortion of the lung

Increase volume of hemithorax

Displacement of mediastiumum

Depressed diaphragm

Increased intercostal space

Pneumomoediastinum and

subcutaneous emphysema

Emphysema

Pneumoperitoneum

Pleural fluid

It takes about 200-300 ml of fluid before it

comes visible on an CXR (figure).

About 5 liters of pleural fluid are present

when there is total opacification of the

hemithorax.

A small right-sided pleural

effusion.

A massive left-sided pleural

effusion.

A loculated (trapped) effusion.

Pleural plaques

They have irregular shapes and do not look like

a lung masses or consolidations.

Some of these opacities are clearly bordering

the chest wall (red arrows).

All these findings indicate that we are dealing

asbestos related pleural plaques:

- bilateral and extensive,

- covering the dome of the diaphragm.

Pleural plaques

Unilateral pleural calcifications are usually

due to:

- infection (TB) ,

- empyema ,

- hemorrhagic .

Mesothelioma

Rib fracture – US is more

sensitive in etection of isolated

rib fracture then CXR.

Atelectasis and air space

consolidation with air

bronchogram of the lower lobe

and pleural effusion.

Empyema with septations

and atelectasis of the lower

lobe on the right side and

atelectasis of the left lower

lobe and echofree pleural

fluid.

Pulmonary embolism with multiple

non vascularized wedge shaped

hypoechoic pleural based lesions

Lung metastases with multiple

hypoechoic masses

CXR: clinical respiratory symptoms/general

check-up/trauma.

CT: detailed charcterization of CXR findings/

oncological chec-up/detection of mets/

staging of ca/characterization of solitary nodule/

trauma.

PET: characterization of nodule/staging/

onkological check-up.

US: detection and estimation of fluid.

Recently - diagnosis of pneumonia

Heart:

- position, size, configuration.

Pulmonary vessels:

- size, position.

Mediastinum:

- trachea, Ao, SVC, AV.

Hila:

- position, size, density.

Lungs:

- contours, lesions/diffuse changes/opacity.

Pleura:

- effusion, pneumothorax, plaques,

thickening, calcifications.

Bones:

- sternum, ribs, spinal collumn

and others.

Diaphragm:

- position, free gas, hernia.

GIT:

- localisation of gas (stomach

buble, colon).

Breast:

- contours, lesions.

Axilla, neck:

- masses.

Lines, tubes and foregin bodies.

Pulmonary embolism

Tuberculosis

Sarcoidosis

Staphylococcal pneumonia

„Inhalation” diseases f.e. siliconosis