Chest radiology part 3

Gamal Rabie Agmy, MD, FCCP

Professor of Chest Diseases, Assiut University

ERS National Delegate of Egypt

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

Lung Cancer / Squamous Cell

Mass density

Anterior segment of LUL

Thick wall cavitation

Squamous Cell Carcinoma

Anterior segment of LUL

Thick wall

Fluid level

Full hilum

Squamous Cell Carcinoma Lung

Thick wall

Irregular lumen

left hilar LN

Etiology:

Cavity can be encountered in practically most lung

diseases.

Common diseases and their characteristics include:

Primary Lung Cancer Thick wall

Shaggy lumen

Eccentric cavitation

Necrotizing Pneumonia

Lung abscess Gravity dependant segments

Thick wall

Air-fluid levels

Tuberculosis

Superior segments Infiltrate around

Bilateral

Fungal infections

Aspergillus

Fungous ball Sub acute invasive aspergillosis

Metastatic disease

Thin walled (Squamous cell)

Thick wall (Adenoma)

Diffuse Alveolar Pneumonia

The most common causes for diffuse alveolar pneumonia are:

Pneumocystis

Cytomegalovirus

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

Necrotizing Pneumonia / Lung Abscess / Aspiration

Superior segment RLL dense pneumonia

Progression / Cavity

Radiation Pneumonia

Post Mediastinal Radiation

Air space disease (air bronchogram)

Over radiation port (vertical and paramediastinal) Bilateral

Progression to fibrosis

Round Pneumonia

Round density

Shorter doubling time

Air bronchogram

The most common causes for round pneumonia are: Fungal

Tuberculosis

Consolidation / Lingula

Density in left lower lung field

Loss of left heart silhouette

Diaphragmatic silhouette intact

No shift of mediastinum Blunting of costophrenic angle

Lateral

Lobar density

Oblique 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

Consolidation Right Upper Lobe /

Air Bronchogram

Density in right upper lung field

Lobar density

Loss of ascending aorta silhouette No shift of mediastinum

Transverse fissure not significantly shifted

Air bronchogram

Pneumoperitoneum

Air under diaphragm

Elevated Diaphragm"

Note pneumoperitoneum

Supradiaphragmatic mass

Can be mistaken for elevated diaphragm

Pellets

Alveolar Cell Carcinoma - Progression

Old film on left

Solitary pulmonary nodule resected

Onset of diaphragmatic paralysis

Progression to multicentric acinar nodules

Hyperlucent Lung

Factors

Vasculature: Decrease

Air: Excess Tissue : Decrease

Bilateral diffuse

Emphysema

Asthma

Unilateral Swyer James syndrome

Agenesis of pulmonary artery

Absent breast or pectoral muscle

Partial airway obstruction

Compensatory hyperinflation Localized

Bullae

Westermark's sign : Pulmonary embolus

Agenesis of Left Pulmonary Artery

Missing vascular markings in left lung

Left hilum not seen

Entire cardiac output to right lung

Missing Right Breast

"Hyperlucent" right base secondary to missing breast.

Unilateral Hyperlucent Lung

Left Upper Lobe Resection

Left lung hyper lucent

Left hilum pulled up

No abnormal density

Pneumomediastinum

Alveolar Proteinosis

Bilateral diffuse alveolar disease

Butterfly pattern

Medullary distribution

Air bronchograms

Adult Respiratory Distress Syndrome

Non-cardiogenic pulmonary edema

Distinguishing characteristics:

Normal size heart

No pleural effusion

Foreign Body Aspiration

Chest Tubes

Achalasia of

esophagus

• Inhomogeneous

cardiac density:

Right half more

dense than left

• Density crossing

midline (right black

arrow)

• Right sided inlet to

outlet shadow

• Right para spinal line

(left black arrow)

• Barium swallow

below: Dilated

esophagus

Aortic Aneurysms

• Location – Ascending / Anterior mediastinum

– Arch / Middle mediastinum

– Descending / Posterior mediastinum

• Characteristics – Mediastinal "mass" density

– Extrapleural

– Calcification of wall

• Dissecting – Inward displacement of calcified intima

– Wavy margin – Inlet to outlet shadow

– Left pleural effusion

Dissecting Aneurysm

Mediastinal widening

Inlet to outlet shadow

on left side

Retrocardiac: Intact silhouette of left heart

margin

Pulmonary artery

overlay sign: Density

behind left lower lobe Wavy margin

Pulmonary Metastsis

Colon in front of liver

Lymph Nodes

Thrombotic Pulmonary Embolism

Thrombotic Pulmonary Embolism

Thrombotic Pulmonary Embolism

Embolism Nonthrombotic Pulmonary

Embolism Nonthrombotic Pulmonary

Embolism Nonthrombotic Pulmonary

Embolism Nonthrombotic Pulmonary

Embolism Nonthrombotic Pulmonary

of PE Diagnostic Algorithm

1. Patients with normal chest radiographic findings

are evaluated with a perfusion scan and, if

necessary, an aerosol ventilation scan. Patients

with normal or very low probability scintigraphic

findings are presumed not to have pulmonary

emboli .

2-Patients with a high-probability scan usually

undergo anticoagulation therapy. All other patients

should be evaluated with helical CT pulmonary

angiography, conventional pulmonary

angiography, or lower-extremity US, depending on

the clinical situation

of PE Diagnostic Algorithm 3-Patients with abnormal chest radiographic findings, are

unlikely to have definitive scintigraphic findings. These

patients undergo helical CT pulmonary angiography as well

as axial CT of the inferior vena cava and the iliac, femoral,

and popliteal veins. If the findings at helical CT pulmonary

angiography are equivocal or technically inadequate (5%–

10% of cases) or clinical suspicion remains high despite

negative findings, additional imaging is required.

4-Patients who have symptoms of deep venous thrombosis

but not of pulmonary embolism initially undergo US, which

is a less expensive alternative. If the findings are negative,

imaging is usually discontinued; if they are positive, the

patient is evaluated for pulmonary embolism at the

discretion of the referring physician.

Developmental Anomalies

Developmental Anomalies

Developmental Anomalies

Developmental Anomalies

Developmental Anomalies

Pulmonary A-V Malformations

Pulmonary Edema

Pulmonary Artery Aneurysms

Pulmonary Artery Aneurysms

Pulmonary –Systemic Communications

Pulmonary –Systemic Communications

Pulmonary –Systemic ommunications

Abnormal Systemic Arteries

Pulmonary Hypertension

Pulmonary Hemorrhage

Pneumomediastinum

Potential Sources of Mediastinal Air

Intrathoracic Trachea and major bronchi

Esophagus

Lung

Pleural space

Extrathoracic Head and neck

Intraperitoneum and retroperitoneum

Radiographic Signs of Pneumomediastinum

Subcutaneous emphysema

Thymic sail sign

Pneumoprecardium

Ring around the artery sign

Tubular artery sign

Double bronchial wall sign

Continuous diaphragm sign

Extrapleural sign

Air in the pulmonary ligament

Mediastinal Cysts

The CT features of benign

mediastinal cyst are

(a) a smooth, oval or tubular mass with a well-

defined thin wall that usually enhances after

intravascular administration of contrast

material,

(b) homogeneous attenuation, usually in the

range of water attenuation (0–20 HU),

(c) no enhancement of cyst contents, and

(d) no infiltration of adjacent mediastinal

structures.

Cysts that contain serous fluid typically have

long T1 and T2 relaxation values, which

produce low signal intensity on T1-weighted

MR images and high signal intensity on T2-

weighted images.

Because cysts containing nonserous

fluid can have high attenuation at CT,

they may be mistaken for solid

lesions. MR imaging can be useful in

showing the cystic nature of these

masses because these cysts continue

to have characteristically high signal

intensity when imaged with T2-

weighted sequences regardless of the

nature of the cyst contents

Radionuclide imaging can be helpful in

detecting functioning thyroid tissue

(iodine-123 or I-131) or parathyroid

tissue (technetium-99m sestamibi) in

the mediastinal cystic mass . gallium-

67 scintigraphy may show increased

radiotracer uptake in the cystic

malignancy owing to necrosis such as

lymphoma or metastatic carcinoma.

Ultrasonography (US) can be useful in

evaluating a mass adjacent to the

pleural surface or cardiophrenic angle.

At US, the benign cysts typically

appear as anechoic thin-walled

masses with increased through

transmission

Bronchogenic Cysts

Duplication Cyst

Pericardial Cyst

Meningocele

Thymic Cysts

Cystic Teratoma

Lymphangioma

Cystlike Lesions

•Mediastinal Pancreatic Pseudocyst

Mediastinal Abscess