chest radiology part 2

Gamal Rabie Agmy, MD, FCCP

Professor of Chest Diseases, Assiut University

ERS National Delegate of Egypt

The definition of atelectasis is loss of air in the alveoli;

alveoli devoid of air (not replaced).

A diagnosis of atelectasis requires the following:

1-A density, representing lung devoid of air

2-Signs indicating loss of lung volume

Atelectasis

1-Absorption Atelectasis When airways are obstructed there is no further

ventilation to the lungs and beyond. In the early

stages, blood flow continues and gradually the

oxygen and nitrogen get absorbed, resulting in

atelectasis.

Types of Atelectasis:

2-Relaxation Atelectasis The lung is held close to the chest wall because of the

negative pressure in the pleural space. Once the

negative pressure is lost the lung tends to recoil due

to elastic properties and becomes atelectatic. This

occurs in patients with pneumothorax and pleural

effusion. In this instance, the loss of negative

pressure in the pleura permits the lung to relax, due

to elastic recoil. There is common misconception that

atelectasis is due to compression.


3-Adhesive Atelectasis :

Surfactant reduces surface tension and keeps the

alveoli open. In conditions where there is loss of

surfactant, the alveoli collapse and become

atelectatic. In ARDS this occurs diffusely to both

lungs. In pulmonary embolism due to loss of blood

flow and lack of CO2, the integrity of surfactant

gets impaired.



4-Cicatricial Atelectasis

– Alveoli gets trapped in scar and

becomes atelectatic in fibrotic

disorders

.

5-Round Atelectasis An instance where the lung gets trapped by

pleural disease and is devoid of air.

Classically encountered in asbestosis.


Generalized 1-Shift of mediastinum: The trachea and heart gets shifted

towards the atelectatic lung.

2-Elevation of diaphragm: The diaphragm moves up and

the normal relationship between left and right side gets

altered.

3-Drooping of shoulder.

4-Crowding of ribs: The interspace between the ribs is

narrower compared to the opposite side.

Signs of Loss of Lung Volume:

Movement of Fissures You need a lateral view to appreciate the movement of

oblique fissures. Forward movement of oblique fissure in

LUL atelectasis. Backward movement in lower lobe

atelectasis.

Movement of transverse fissure can be recognized in the

PA film.


Movement of Hilum The right hilum is normally slightly lower than the left.

This relationship will change with lobar atelectasis.


Compensatory Hyperinflation

Compensatory hyperinflation as evidenced by increased

radiolucency and splaying of vessels can be seen with the

normal lobe or opposite lung.


Alterations in Proportion of Left and

Right Lung

The right lung is approximately 55% and left lung 45%. In

atelectasis this apportionment will change and can be a

clue to recognition of atelectasis. .


Hemithorax Asymmetry In normals, the right and left hemithorax are equal in size.

The size of the hemithorax will be asymmetrical and

smaller on the side of atelectasis


Signs of Loss of Lung Volume: Generalized

Shift of mediastinum: The trachea and heart gets shifted towards the atelectatic lung.

Elevation of diaphragm: The diaphragm moves up and the normal relationship between left

and right side gets altered.

Drooping of shoulder.

Crowding of ribs: The interspace between the ribs is narrower compared to the opposite side.

Movement of Fissures

You need a lateral view to appreciate the movement of oblique fissures. Forward movement of

oblique fissure in LUL atelectasis. Backward movement in lower lobe atelectasis.

Movement of transverse fissure can be recognized in the PA film.

Movement of Hilum

The right hilum is normally slightly lower than the left. This relationship will change with lobar

atelectasis.

Compensatory Hyperinflation

Compensatory hyperinflation as evidenced by increased radiolucency and splaying of vessels

can be seen with the normal lobe or opposite lung.

Alterations in Proportion of Left and Right Lung

The right lung is approximately 55% and left lung 45%. In atelectasis this apportionment will

change and can be a clue to recognition of atelectasis.

Hemithorax Asymmetry

In normals, the right and left hemithorax are equal in size. The size of the hemithorax will be

asymmetrical and smaller on the side of atelectasis

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

Left Lower Lobe Atelectasis • Inhomogeneous cardiac density

• Left hilum pulled down

• Non-visualization of left diaphragm

• Triangular retrocardiac atelectatic LLL

Atelectasis Left Lower Lobe Double density over heart

Inhomogenous cardiac density

Triangular retrocardiac density

Left hilum pulled down

Other findings include:

Pneumomediastinum

Atelectasis Left

Upper Lobe

Mediastinal shift to left

Density left upper lung field Loss of aortic knob and left hilar

silhouettes

Herniation of right lung

Atelectatic left upper lobe

Forward movement of left

oblique fissure "Bowing sign"

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

Lateral Movement of oblique and transverse fissures

Atelectasis Right Upper Lobe

Homogenous density right upper lung

field


Loss of silhouette of ascending aorta

Lateral Movement of oblique and transverse fissures

Atelectasis Right Upper Lobe

Homogenous density right upper lung field


Loss of silhouette of ascending aorta

RML Atelectasis

Vague density in right lower lung field, almost normal

RML atelectasis in lateral view, not evident in PA view

Vague density in right lower lung field (almost a normal film).

Dramatic RML atelectasis in lateral view, not evident in PA view. Movement of

transverse fissure.

Other findings include: Azygous lobe

Atelectasis Right Lower Lobe Density in right lower lung field Indistinct right diaphragm

Right heart silhouette retained

Transverse fissure moved down

Right hilum moved down

Adhesive Atelectasis

Alveoli are kept open by the integrity of surfactant. When there is loss

of surfactant, alveoli collapse. ARDS is an example of diffuse alveolar

atelectasis.

Plate-like atelectasis is an example of focal loss of surfactant.

Relaxation Atelectasis

The lung is held in apposition to the chest wall because of negative pressure

in the pleura. When the negative pressure is lost, as in pneumothorax or

pleural effusion, the lung relaxes to its atelectatic position. The atelectasis is

a secondary event. The pleural problem is primary and dictates other radiological findings.

Round Atelectasis

Mass like density

Pleural based

Base of lungs

Blunting of costophrenic angle Pleural thickening

Pulmonary vasculature curving

into the density

Esophageal surgical clips

Round Atelectasis

Mass like density

Pleural based

Base of lungs

Blunting of costophrenic angle, pleural thickening Pulmonary vasculature curving into the density

RML Lateral Segment Atelectasis

Sub-segmental Atelectasis

Atelectasis

Segmental

Anterior sub-segment of RUL

"Bronchial wedge"

Hilar Displacement

Bronchiectasis

Left lung atelectasis due to mucus plugging

Mucus plugs suctioned with bronchoscopy

Bronchogram done after bronchoscopy

Saccular bronchiectasis in bronchogram below

Bronchogram

Bronchograms are rarely done nowadays. The need for it

disappeared with the invention of the fiberoptic

bronchoscopy and high resolution CT scan. View these images to get a greater understanding of a three

dimensional view of a bronchial tree..

Bronchogram

Bronchograms are rarely done nowadays. The need for it disappeared with the

invention of the fiberoptic bronchoscopy and high resolution CT scan.

Calcification

Focal lung lesion: Ghon's complex

Miliary lung calcification:

Histoplasmosis

Tuberculosis

Alveolar microlithiasis

Chicken pox pneumonia

Solitary pulmonary nodule :

Central / Granuloma

Lamellar / Histoplasmosis

Pop corn / Hamartoma

Eccentric / Scar Cancer

Calcification

Nodes:

Homogenous / TB

Clumpy / Histoplasmosis

Egg shell / Silicosis, Sarcoidosis

Tracheal cartilage : Aging

Tumor:

Mediastinal mass / Teratoma

Healed lymphoma / Metstasis

Calcification

Vascular:

Aortic calcification

Pulmonary artery calcification

Pulmonary hypertension

Pleural:

Visceral / Hemothorax, TB, Empyema

Parietal / Asbestosis

Subcutaneous calcification:

Cysticercus

Broncholith

Subsegmental atelectasis

Calcified node

Broncholith obstructing bronchus

Silicosis Egg shell calcification of lymph nodes

Other findings include:

Diaphragmatic pleural calcification

Multiple cavities with fluid levels

Histoplasmosis

Calcified nodes

Clumpy calcification Calcified nodules in lungs

Hamartoma

Popcorn calcification

Pleural Calcification

Visceral pleural

calcification

Parietal pleura appears

black because it is sandwiched between

bony densities

Pleural Calcification Visceral pleura

Old TB

Visceral pleural calcification

Open drainage with air fluid levels in pleural space

Subcutaneous calcification

Cavitary Lung Lesions

Number:

Multiple bilateral cavities would raise

suspicion for either bronchiogenous or

hematogenous process. You should consider:

Aspiration lung abscess

Septic emboli

Metastatic lesions

Vasculitis (Wegener's)

Coccidioidomycosis, tuberculosis

Location:

• Classical locations for aspiration lung abscess are superior segment of the lower lobes posterior segments of upper lobes.

• Tuberculous cavities are common in superior segments of upper and lower lobes or posterior segments of upper lobes.

• When a cavity in anterior segment is encountered, a strong suspicion for lung cancer should be raised. TB and aspiration lung abscess are rare in anterior segments. Cancer lung can occur in any segment.

Wall Thickness:

• Thick walls are seen in:

– Lung abscess

– Necrotizing squamous cell lung cancer

– Wegener's granulomatosis

– Blastomycosis

Wall Thickness:

• Thin walled cavities are seen in:

• Coccidioidomycosis

• Metastatic cavitating squamous cell carcinoma from the cervix

• M. Kansasii infection

• Congenital or acquired bullae

• Post-traumatic cysts

• Open negative TB

Contents:

• The most common cause for air fluid level is lung abscess. Air fluid levels can rarely be seen in malignancy and in tuberculous cavities from rupture of Rasmussen's aneurysm.

• A fungous ball should make you consider aspergillosis. A blood clot and fibrin ball will have the same appearance.

• Floating Water Lily: The collapsed membrane of a ruptured echinococcal cyst, floats giving this appearance.

Lining of Wall:

The wall lining is irregular and nodular in

lung cancer or shaggy in lung abscess

Evolution of Lesion:

Many times review of old films to assess the

evolution of the radiological appearance of

the lesion extremely helpful. Examples

• Infected bullae

• Aspergilloma

• Sub acute necrotizing aspergillosis

• Bleeding from Rasmussen's aneurysm in a

tuberculous cavity

Associated Features:

Ipsilateral lymph nodes or lytic

lesions of the bone is seen

with malignancy

Bulla<1mm wall

>1cm size

Pneumatocele<1mm wall

staph. infection

Honey combing<1cm size

multiple equal

Cyst1-3mm wall

1-10 cm size

Cavity>3mm wall

Any size

Cavitary lesions of lung

Bulla

Definition

•Thin-walled–less than 1 mm

•Air-filled space

•In the lung> 1 cm in size and up to 75% of lung

•Walls may be formed by pleura, septa,

or compressed lung tissue.

•Results from destruction, dilatation and

confluence of airspaces distal to terminal

bronchioles.

•Bullous disease may be primary or associated

with emphysema or interstitial lung disease.

• Primary bullous lung disease may be familial

and has been associated with Marfan's, Ehler's

Danlos, IV drug users, HIV infection, and

vanishing lung syndrome.

•Bullae may occasionally become very large

and compromise respiratory function. Thus

has been referred as vanishing lung syndrome,

and may be seen in young men.

Upper lobe Bulla

Lower lobe Bulla

A: Xray shows bilateral bulla.

B: CT shows bilateral bulla.

C: CT after bullectomy.

Pneumatocele is a benign air containing cyst of lung, with

thin wall < 1mm as bulla but with different mechanism

Infection with staph aureus is the commonest cause ( less

common causes are, trauma, barotrauma) lead to necrosis

and liquefaction followed by air leak and subpleural

dissection forming a thin walled cyst.

•Honeycombing is defined as multiple cysts < 1cm in diameter,with

well defined walls, in a background of fibrosis, tend to form

clusters and is considered as end stage lung .

•It is formed by extensive interstitial fibrosis of lung with residual

cystic areas.

A cyst is a ring

shadow > 1 cm in

diameter and up to

10 cm with wall

thickness from 1-3

mm.

Thin walled cysts of LAM

A cavity is > 1cm

in diameter, and its

wall thickness is

more than 3 mm.

•A central portion necrosis and communicate to bronchus.

•The draining bronchus is visible (arrow). CT (2 mm slice thickness)

shows discrete air bronchograms in the consolidated area.

Mechanism

1. Site

A cavity in apicoposterior segment of left upper lobe

2.Number

Multiple cavities:

1. Aspiration.

2. TB

3. Fungal.

4. Metastatic.

5. Septic emboli.

6.Wegners granulomatosis

Multiple cysts of metastasis

from squamous cell

carcinoma.

Multiple thick wall cavities from

adenocarcinoma of right lung

Irregular , nodular inner lining of thick wall abscess

Malignant cavity.

3. Thickness and

irregularity

4. eccentric

Malignant

5. Relation to lymph

node enlargement

6. Contents

•Arrow head Crescent sign.

•Black arrows Fibrotic bands surrounding cavity

(Fibrocavitary TB).

Primary Lung Cancer

• Thick wall

• Shaggy lumen

• Eccentric cavitation

|

Squamous Cell Carcinoma Lung

LUL mass

Thick walled cavity

Eccentric location of cavity

Fungous Ball Long standing cavity

Containing round density (A)

Mobile density Adjacent pleural reaction (B) - characteristic of aspergilloma

Cavitating Metastasis

Multiple Thin Walled Cavities

Cancer Cervix

chest radiology part 2

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