Gamal Rabie Agmy, MD, FCCP

Professor of Chest Diseases, Assiut University

ERS National Delegate of Egypt

L:Lung

R:Rib

T:Trachea

AK:Aortic knob

A:Ascending aorta

H:Heart

V: Vertebra

P: Pulmonary

artery

S:Spleen

Missing Right Breast

"Hyperlucent" right base secondary

to missing breast.

Silicone Breast Implantation

Cancer Breast

Larger right breast Inverted nipple

Radiation Fibrosis of

Lung

Right lung smaller

Right hemithorax smaller

Paramediastinal fibrosis

Cervical Rib

Pleural Effusion / Lytic Lesions in Clavicle and Scapula

Cervical rib

Kyphoscoliosis

Rib Fracture / Hematoma

Extra Pleural Sign

Cancer Lung

Density in periphery

Sharp inner margin

Indistinct outer margin Angle of contact with chest wall

Expanding destructive rib lesion

Paratracheal widening

This is an example of an RUL lesion

Neurofibromatosis

Sprengel's Deformity

High set scapula

Vertebral anomaly

Rib anomaly

Subcutaneous Emphysema

Air outlining pectoral muscles

Air along chest wall

Pneumomediastinum

Lateral Chest

There is valuable information that can be obtained by a chest

lateral view. A few of them are listed below:

Sternum

Vertebral column Retrosternal space

Localization of lung lesions

Lobes of lungs

Oblique fissures

Pulmonary artery Heart

Aorta

Mediastinal masses

Diaphragm

Volume measurements SPN

Radiologic TLC

Tracheoesophageal stripe

Tuberculosis of Spine

Loss of intervertebral space

Vertebral collapse

Cold abscess is not present in this case. PA view is not diagnostic.

Mediastinal Lymph Nodes

Extrapleural

Polycyclic margin

Anterior mediastinum

RML Atelectasis

Vague density in right lower lung field, almost normal

RML atelectasis in lateral view, not evident in PA view

Atelectasis Left Upper

Lobe

Hazy density over left

upper lung field

Loss of left heart silhouette

Tracheal shift to left

A: Forward movement of oblique

fissure

C: Atelectatic LUL

B: Herniated right lung

Localization

When a lesion is not contiguous to a

silhouette, it is not possible to localize it

without a lateral view. This is a case of a

solitary pulmonary nodule with popcorn calcification: Hamartoma.

Air Bronchogram

• In a normal chest x-ray, the tracheobronchial tree is not

visible beyond the 4th order. As the bronchial tree

branches, the cartilaginous rings become thinner, and

eventually disappear in respiratory bronchioles. The

lumen of the bronchus contains air and the surrounding

alveoli contain air. Thus, there is no contrast to visualize

the bronchi.

• The air column in the bronchi beyond the 4th order

becomes recognizable if the surrounding alveoli is filled,

providing a contrast or if the bronchi get thickened

• The term air bronchogram is used for the former state

and signifies alveolar disease.

Silhouette Sign

Adjacent Lobe/Segment Silhouette

RLL/Basal segments Right diaphragm

RML/Medial segment Right heart margin

RUL/Anterior segment Ascending aorta

LUL/Posterior segment Aortic knob

Lingula/Inferior segment Left heart margin

LLL/Superior and basal segments Descending aorta

LLL/Basal segments Left diaphragm

Cardiac margins are clearly seen because there is contrast between the fluid

density of the heart and the adjacent air filled alveoli. Both being of fluid density,

you cannot visualize the partition of the right and left ventricle because there is no

contrast between them. If the adjacent lung is devoid of air, the clarity of the

silhouette will be lost. The silhouette sign is extremely useful in localizing lung lesions.

Atelectasis Right Lung Homogenous density right hemithorax

Mediastinal shift to right

Right hemithorax smaller

Right heart and diaphragmatic silhouette are not identifiable

Atelectasis Left Lung

Homogenous density left hemithorax Mediastinal shift to left

Left hemithorax smaller

Diaphragm and heart silhouette are not identifiable

Atelectasis Left Lung

•Homogenous density lef t hemithorax •Mediastinal shif t to the lef t

•Lef t hemithorax smaller •Diaphragmatic and heart silhouette are not identif iable

Lateral Movement of oblique and transverse fissures

Atelectasis Right Upper Lobe

Homogenous density right upper lung

field

Mediastinal shift to right

Loss of silhouette of ascending aorta

Atelectasis Left Upper

Lobe

Hazy density over left

upper lung field

Loss of left heart silhouette

Tracheal shift to left

Lateral A: Forward movement of

oblique fissure

B: Herniated right lung

C: Atelectatic LUL

Consolidation Right

Upper Lobe /

Density in right upper lung

field Lobar density

Loss of ascending aorta

silhouette

No shift of mediastinum

Transverse fissure not significantly shifted

Air bronchogram

Consolidation Left Lower Lobe

Density in left lower lung field

Left heart silhouette intact

Loss of diaphragmatic silhouette

No shift of mediastinum Pneumatocele

One diaphragm only visible

Lobar density

Oblique fissure not significantly

shifted

Left Upper Lobe Consolidation

Density in the left upper lung field

Loss of silhouette of left heart margin

Density in the projection of LUL in lateral view

Air bronchogram in PA view No significant loss of lung volume

Vague density right lower lung field

Indistinct right cardiac silhouette

Intact diaphragmatic silhouette

Density corresponding to RML

No loss of lung volume

RML pneumonia

S Curve of Golden

When there is a mass

adjacent to a fissure, the

fissure takes the shape

of an "S". The proximal convexity is due to a mass,

and the distal concavity is

due to atelectasis. Note the

shape of the transverse

fissure. This example represents a

RUL mass with atelectasis

Tracheal Shift

Trachea is index of upper mediastinal position. The pleural pressures on either

side determine the position of the mediastinum. The mediastinum will shift towards the side with relatively higher negative pressure compared to the opposite side. Tracheal deviation can occur under the following conditions:

• Deviated towards diseased side – Atelectasis

– Agenesis of lung

– Pneumonectomy

– Pleural fibrosis

• Deviated away from diseased side – Pneumothorax

– Pleural effusion

– Large mass

• Mediastinal masses

• Tracheal masses

• Kyphoscoliosis

Atelectasis Right Lung

• Homogenous density

right hemithorax

• Mediastinal shift to right

• Right hemithorax smaller

• Right heart and

diaphragmatic silhouette

are not identifiable

•

Pleural Effusion Massive

• Unilateral homogenous

density

• Mediastinal shift to right

• Left diaphragmatic and

left heart silhouettes lost

• Left hemithorax larger

Pneumonectomy

• Opacity left

hemithorax

• Tracheal shift to left

• Cardiac and left

diaphragmatic

silhouettes missing

• Crowding of ribs

Air Bronchogram

• In a normal chest x-ray, the tracheobronchial tree is not

visible beyond the 4th order. As the bronchial tree

branches, the cartilaginous rings become thinner, and

eventually disappear in respiratory bronchioles. The

lumen of the bronchus contains air and the surrounding

alveoli contain air. Thus, there is no contrast to visualize

the bronchi.

• The air column in the bronchi beyond the 4th order

becomes recognizable if the surrounding alveoli is filled,

providing a contrast or if the bronchi get thickened

• The term air bronchogram is used for the former state

and signifies alveolar disease.

Bowing Sign

• In LUL atelectasis or

following resection, as in

this case, the oblique

fissure bows forwards

(lateral view). Bowing

sign refers to this feature.

The arrow points to the

forward movement of the

left oblique fissure.

Doubling Time

• Time to double in volume (not diameter)

• Useful in determining the etiology of solitary

pulmonary nodule

• Utility

– Less than 30 days: Inflammatory process

– Greater than 450 days: Benign tumor

– Malignancy falls in between

Eccentric Location of Cavity in a

Mass

• Thick wall and irregular lumen can be

seen in both malignancy and

inflammatory lesions.

• However eccentric location of cavity is

diagnostic of malignancy.

• This is an example of squamous cell carcinoma lung.

• LUL mass

• Thick walled cavity

• Eccentric location of cavity

• Fluid level

• This is diagnostic of malignancy.

Cortical Distribution

• Mirror image of pulmonary edema

• Alveolar disease of outer portion of lung

• Encountered in:

– Eosinophilic pneumonia

– Bronchiolitis obliterans with pneumonia

Medullary Distribution

• It is also called "butterfly pattern"

• Note the sparing of lung periphery both in

the CT, PA and lateral views

• This is one of the radiologic signs

indicative of diffuse alveolar disease

• This is an example of alveolar proteinosis.

Note the sparing of lung periphery both in the CT, and PA view

This is one of the radiologic signs indicative of diffuse alveolar disease

This is an example of alveolar proteinosis.

Diffuse Alveolar Disease

Radiological Signs

• Butterfly distribution / Medullary distribution

• Lobar or segmental distribution

• Air bronchogram

• Alveologram

• Confluent shadows

• Soft fluffy edges

• Acinar nodules

• Rapid changes

• No significant loss of lung volume

• Ground glass appearance on HRCT

Distribution

• Cortical

– Eosinophilic pneumonia

– BOOP

• Lower lobes / Mineral oil aspiration

• Medullary

Acute Diffuse Alveolar Disease

• Water

– Pulmonary edema, Cardiogenic, Neurogenic pulmonary edema • Blood

– SLE

– Goodpasture's syndrome

– Idiopathic pulmonary hemosiderosis

– Wegener's granulomatosis • Inflammatory

– Cytomegalovirus pneumonia

– Pneumocystis carinii pneumonia

– Influenza

– Chicken pox pneumonia • Fat embolism

• Amniotic fluid embolism

• Adult respiratory distress syndrome

Acinar Nodules

Interstitial Acinar

Same size

Sharp edges

smaller

Varying in size

Indistinct edges

Larger than interstitial nodules

Acinar nodules are difficult to distinguish from interstitial

nodules. Some distinguishing characteristics are as follows:

Cut Off Sign

• When you see an abrupt ending of visualized

bronchus, it is called a "cut off sign". It indicates

an intrabronchial lesion. This is useful to identify

the etiology of atelectasis . Be careful as the

tracheobronchial tree is three dimensional and

the finding need to be confirmed with tomogram.

In the modern era, a CT scan will take care of

this.

Air Fluid Level

Causes • Cavities

• Pleural space: Hydropneumothorax

• Bowel: Hiatal hernia

• Esophagus: Obstruction

• Mediastinum: Abscess

• Chest wall

• Normal stomach

• Dilated biliary tract

• Sub diaphragmatic abscess

Wedge Shaped Density The wedge's base is pleural

and the apex is towards the

hilum, giving a triangular

shape. You can encounter

either of the following:

Vascular wedges :

Infarct

Invasive aspergillosis

Bronchial wedges :

Consolidation

Atelectasis

Polycyclic Margin The wavy shape of

the mediastinal mass

margin indicates that

it is made up of

multiple masses,

usually lymph nodes.

This is a case of

lymphoma.

Open Bronchus Sign / Alveolar Atelectasis

The right lung is atelectatic. You can see air bronchogram, which indicates

that the airways are patent .This case is an example of adhesive alveolar

atelectasis.

Pulmonary Artery Overlay

Sign

This is the same concept as

a silhouette sign. If you can

recognize the interlobar pulmonary artery, it means

that the mass seen is either

in front of or behind it.

This is an example of a

dissecting aneurysm.

S Curve of Golden

When there is a mass

adjacent to a fissure, the

fissure takes the shape

of an "S". The proximal convexity is due to a mass,

and the distal concavity is

due to atelectasis. Note the

shape of the transverse

fissure. This example represents a

RUL mass with atelectasis

Tracheoesophageal Stripe

The posterior wall of the trachea (T)

and the anterior wall of the esophagus

(E) are in close contact and form the

tracheoesophageal stripe in the lateral view (arrow).

It is considered abnormal when it is

wider than __ mm.

Common causes for thickening of

tracheoesophageal stripe are:

Esophageal disease

Nodal enlargement

AV Fistula

Osler-Weber-Rendu

Syndrome

"Pulmonary nodule"

Multiple lesions Feeding vessel

Cardiomegaly

Patient presented with

severe congestive heart failure and severe iron

deficiency anemia. Had

multiple telangiectasia of

tongue, lips and

conjunctivae.

Pneumonectomy

Diffuse haziness

Smaller right hemithorax

Mediastinal shift to right Surgical clips