AIRWAYS DISEASE & COLLAPSE

MODERATOR: DR. KANCHAN DHUNGEL PRESENTER: DR ABHISHEK

CONTENTS• ANATOMY

• CONGENITAL TRACHEO-BRONCHIAL ANOMALY

• BRONCHIECTASIS

• EMPHYSEMA

• BRONCHIAL ASTHMA

• CHRONIC BRONCHITIS

• BRONCHIOLITIS

• COLLAPSE OF LUNG

STRUCTURAL ANATOMY

STRUCTURAL ANATOMY

The right main bronchus is wider, shorter, and more vertical than the left main bronchus

STRUCTURAL ANATOMY

Trachea - cartilaginous and fibro-muscular conduit for ventilation and bronchial secretions.

Extends from C6 (cricoid cartilage) to carina

Carina - T4-T5

In adults, its length ~ 11-13 cm with 2-4 cm being extra-thoracic. However , length is dynamic.

The trachea has 16 to 22 horseshoe bands of cartilage that compose anterior and lateral walls of trachea. The posterior tracheal wall lacks cartilage.

Coronal diameter: Men 13 to 25 mm Women 10 to 21 mm.

Sagittal diameter: Men 13 to 27 mm Women 10 to 23 mm

• Tracheal index : calculated by dividing coronal diameter by the sagittal diameter .

Normal value is ~ 1.

Posterior wall appears thinner and gives a variable contour to shape of trachea due to lack of cartilage.

It may appear flat, convex or slightly concave depending on level of inspiration

Posterior wall of trachea either flattens or bows slightly forward during expiration.

In normal subjects there is up to a 35% reduction in AP tracheal lumen in forced expiration, whereas transverse diameter decreases only by 13%

Axial computed tomography image shows the normal rounded configuration of the trachea at the end of inspiration. Note the normal anterior bowing of the posterior membranous wall of the trachea at the end of expiration

Congenital Tracheo-bronchial anomaly

Bronchus suis Refers to rare congenital anomaly, whereby

right upper lobe bronchus originates directly from trachea

Bronchial Atresia

Developmental disorder, resulting in a segmental

or sub-segmental bronchus becoming entirely detached from main airway.

Distal airway will continue to produce mucus while there is no clearance from airway, leading to impaction of mucus seen as “finger-in-glove” sign on CT

Most commonly in apicoposterior segmental bronchus of the left upper lobe.

CT - central, mass like opacity with a tubular configuration.

Distal segmental branches are dilated and contain secretions. The peripheral lung is hyperexpanded, with decreased attenuation and reduced vasculature.

Bronchial atresia. central tubular structure with hyperlucency of the apicoposterior segment of the left upper lobe.

Tracheo-esophageal fistulaCongenital malformation results from a

failure of the trachea and oesophagus to divide and grow out separately during early development of the primitive foregut.

Often seen in A/W other congenital anomalies, of which the VACTERL is most commonly known

Classification (Gross's Anatomical Classification)Type A: Esophageal atresia without

tracheoesophageal fistula.Type B: Esophageal atresia with proximal

tracheoesophageal fistula.Type C: Esophageal atresia with distal

tracheoesophageal fistula (most common type) (85%).

Type D: Esophageal atresia with proximal and distal fistula.

Type E: Tracheoesophageal fistula without atresia. (Not shown)

TEF. Oblique barium esophagogram demonstrates a fistula (arrow) arising from the anterior esophagus and extending anterosuperiorly to the trachea.

Tracheobronchomegaly (Mounier-kuhn disease)

Characterized by dilatation of trachea and main bronchi owing to severe atrophy of longitudinal elastic fibres and thinning of the muscularis mucosa.

Affected patients typically present during the third and fourth decades with recurrent respiratory infections.

Mounier-Kuhn syndrome. Dilatation of the trachea in association with bronchiectasis (arrows). There are also multiple paraseptal bullae (curved arrow).

Saber sheath tracheaAssociated with COPD or advanced Age

Marked coronal narrowing in the presence of accentuation of the sagittal diameter

Sagittal:Coronal ratio of greater than 2.

Chest radiographs may show diffuse narrowing of trachea on PA view.

CT shows inward bowing of the lateral tracheal wall, which may be accentuated on the expiratory or dynamic CT, with the

classic narrow “saber sheath” shape.

Saber sheath trachea. Chest radiograph PA view demonstrating diffuse narrowing of the trachea CT: inward bowing of the lateral tracheal wall with elongated sagittal dimension of trachea compared to the coronal plane is consistent with the saber sheath configuration.

Relapsing PolychondritisMay be caused by a range of etiologies,

including vasculitis, amyloidosis, infectious processes.

Cartilaginous part of the airway progressively destroyed due to an autoimmune process of recurrent inflammation.

It results in significant airflow obstruction

due to collapse of the trachea and main bronchi during expiration

At expiration, 90% or more patients show signs of collapse (malacia) with or without air trapping.

Calcifications in the airway walls may be seen in approximately 40% of patients.

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CT scan: diffuse thickening of tracheal wall with abnormal calcificationand narrowing of the tracheal lumen. (B) CT scan just below level of cannashows identical abnormalities extending into both main bronchi.

Relapsing polychondritis - characteristic thickening of the anterior cartilaginous wall of the trachea (arrow). The posterior membranous wall is uninvolved.

Tracheobronchial stenosis

Defined as focal or diffuse narrowing of the tracheal lumen and may occur secondary to a wide variety of benign and malignant causes.

Iatrogenic Postintubation

Lung transplantation

Infection Laryngotracheal papillomatosis[*]

Rhinoscleroma Tuberculosis

Tracheal neoplasm

Systemic diseases Amyloidosis

Inflammatory bowel disease Relapsing polychondritis Sarcoidosis Wegener granulomatosis

Subglottic stenosis resulted from prolonged intubation.

Post-intubation tracheal stenosis. A: Coronal and B: sagittal volume-rendered reconstructions demonstrate a 3-cm area of narrowing in the trachea above the thoracic inlet.

Tracheo-bronchial malacia

Tracheobronchomalacia refers to weakness of the airway walls and/or supporting cartilage and is characterized by excessive expiratory collapse

Tracheobronchomalacia may be either congenital or acquired

Risk Factors for Acquired Tracheomalacia COPD

Posttraumatic and iatrogenic factors PostintubationPosttracheostomyRadiation therapyPost lung transplantation

Relapsing polychondritis

Chronic external compression of the trachea Paratracheal neoplasms goiter congenital cyst

Variable degree of collapse of airway during expiration

On CT scans. A “frownlike” tracheal configuration, due to the marked anterior bowing of the posterior membranous wall forming a crescenteric configuration, has been described as Characteristic of tracheomalacia

Main imaging finding

End inspiratory and end expiratory axial computed tomography scan shows excessive collapse of the posterior wall of the trachea in expiration.Note the extensive changes consistent with emphysema in both lungs.

Tracheal neoplasmsUncommon, with 90% being malignant.

Two major types of tracheal carcinomas Squamous cell (55%) Adenocystic (18%)..

Rare hematogenous metastases from melanoma or breast

Malignant neoplasms : CT as an eccentric irregular soft tissue mass within

lumen, most typically arising from posterior and lateral wall

Squamous cell carcinoma of trachea.

Benign tracheal tumors

Squamous papilloma (young children), Pleomorphic adenoma Mesenchymal hamartomathose of cartilaginous

origin.

Well circumscribed/smoothly marginated/< 2 cm in diameter.

BronchiectasisIrreversible localized or diffuse

dilatation of cartilage containing airways or bronchi.

Resulting fromChronic infection Proximal airway obstruction Congenital bronchial abnormality

Causes of Bronchiectasis

Infection – bacteria, mycobacteria, fungus, virus

Acquired bronchial obstruction (neoplasm, foreign body, bronchholith)

Extrinsic bronchial obstruction (lymph node enlargement, neoplasm)

Inherited molecular and cellular defects(cystic fibrosis, a1 antitrypsin deficiency)

Inherited bronchial structural deficiencies(bronchial atresia,congenictal tracheobronchomegaly, Williams-campell syndrome)

Primary ciliary dyskinesia (Kartagener syndrome)

Pulmonary fibrosis(results in traction bronchiectasis)

TYPES

Cylindrical (tubular) uniform mild dilatation with loss of normal tapering of bronchi

Varicose greater dilatation with irregular caliber due to areas of expansion and narrowing.

Cystic (saccular) marked dilatation with peripheral ballooning.

Chest radiographs:

Tram tracks parallel line opacities

Ring opacities

Tubular structures.

Chest radiographs lack sensitivity for detecting mild or even moderate disease.

X ray photo

Multiple ring shadowTramline shadow visuble through heart

CT is more sensitive.

Characterized by lack of bronchial tapering

Bronchi visible in peripheral 1 cm of lungs

Increased bronchoarterial ratio producing the so-called signet-ring sign.

Cylindric Bronchiectasis

Diagnostic criteria bronchial diameter > accompanying artery (signet ring sign)

Lack of bronchial tapering.

Identification of a bronchus within 1 cm of costal pleura or abutting the mediastinal pleura.

signet ring sign

Normal bronchus cylindric bronchiectasis with lack tapering

Cylindrical bronchiectasis

varicoid bronchiectasis

Varicoid bronchiectasis is characterized by a beaded appearance, mimicking a “string of pearls” .

Cystic bronchiectasis

Cystic bronchiectasis is characterized by thin-walled cystic spaces that connect with proximal airways, with or without fluid levels

Cystic bronchiectasis is characterized by thin-walled cystic spaces with fluid levels

Atypical mycobacterial infection:Cylindrcal broncheactasis & centrilobular nodule in middle lobe & lingula

ABPA. Coronal reformation CT image demonstrates impacted bronchi in the left upper lobe producing a “gloved finger” appearance.

Impaction of bronchiectatic airways -tubular opacities with a Y- or V-shaped configuration, often mimicking a “gloved finger”

Impaction of a single bronchus may mimic a parenchymal mass, but careful inspection typically reveals a tubular rather than round configuration

scrolling through a series of axial images or assessment with MPR can be helpful.

Bronchial impaction. A, Axial CT image shows a tubular structure (arrow) in the superior segment of the right lower lobe with no visible aerated bronchus. B, Axial CT image following expectoration of a large mucus plug shows underlying bronchiectasis (arrow).

EMPHYSEMAChronic condition characterized by progressive irreversible

enlargement of airspaces distal to the terminal bronchiole with destruction of the alveolar walls and no obvious fibrosis

Types of emphysema Centrilobular

Panlobular

Paraseptal

Paracicatricial

respiratory bronchioles and the adjacent alveolar spaces, which are located in the centralportion of the secondary pulmonary lobule, are progressively enlarged and destroyed. Lung tissue in the periphery of the lobule is spared initially but may become involved in the hater stages of the disease.

Panlobular EmphysemaAlso K/as panacinar or diffuse emphysema)

Affects entire SPL producing diffuse destruction and enlarged airspaces throughout the lung

Lower lobe predominance in most cases, presumably due to the greater blood flow in this region especially in chronic bronchitis

alfa -1-antitrypsin deficiency.

Main radiological sign :

Hyperinflation of lung

Decrease pulmonary vascularity peripherally

Retrosterrnal air space depth

Heart appears long and narrow

`Barrel chest'

chest radiographs, postero-anterior and lateral views, show hyperinflation of the lungs (flattened diaphragm and widened retrosternal space), increased translucency in the upper lungs with vascular attenuation and distorted arborization

High-resolution computed tomography images through the lung apices and bases demonstrate lower lobe predominate emphysema

Lower-lung predominance, and vascular attenuation are better shown by the coronal minimum intensity projection and maximum intensity projection images .

Centriobular Emphysema (also called centriacinar or proximal acinar emphysema)

Selective process characterized by destruction & dilatation of respiratory bronchioles.

Emphysematous spaces lie near the center of SPL and the lung tissue distal to the emphysematous spaces is often normal . alveolar ducts, sacs and alveoli are spared until a late stage.

Upper zones tend to be more severely involved than the lung bases.

It is usually found in smokers, frequently in association with chronic bronchitis.

Centrilobular emphysema. large irregular areas of lucency, without any definable walls, with a paucity of pulmonary vessels

Paraseptal EmphysemaAlso referred to as distal acinar or localized

Involves the distal portion of the lobule.

Characteristically adjacent to the visceral pleura and interlobular septa, within otherwise normal lung

When these paraseptal cysts exceed 1 cm in size, with an exceedingly thin wall, they may be termed bullae.

Paraseptal emphysema. A and B, HRCT show extensive emphysema in the subpleural regions.

Paracicatrieial Emphysemaalso referred to as irregular or scar emphysema

Distension and destruction of terminal air spaces adjacent to fibrotic lesions.

Causes Tuberculosis (MC), silicosis.

Often associated traction bronchiectasis and honeycomb lung.

(PCE) from progressive massive fibrosis caused by silicosis: conglomerate masses with surrounding low attenuation (arrows) indicating PCE

BullaBullae- usually A/W some form of emphysema

Common - paraseptal emphysema.

Their walls may be visible as a smooth, curved, hairline shadow.

If the walls are not visible, displacement of vessels around a radiolucent area may indicate a huIlous area.

‘Both upper zones are occupied by large bullae which are compressing upper lobes. No evidence of generalised emphysema or air trapping. The level and shape of the diaphragm are normal

coronal computed tomography multiplanar reformation and maximum intensity projection images show a large bulla in the right upper lobe with atelectasis of the adjacent lung

A giant bulla A bulla that takes up a third or more of the space in and around the affected lung is called a giant bulla.

D/D- Loculated Pneumothorax

CT may be necessary to demonstrate the wall of the bulla or thin strands of lung tissue crossing it.

Large bullae can compress adjacent more

compliant lung, producing atelectatic pseudomasses

Predispose to pneumothorax and can reach a very large size.

Atelectatic pseudomass. Computed tomography demonstrates a right paraspinal mass (arrow) with central air bronchograms. A very large bulla almost completely fills the right hemithorax. The mass represented collapsed normal lung that re-expanded following resection of the bulla.

ASTHMAClinical syndrome result from hyper-reactivity of

larger airways to a variety of stimuli, causing narrowing of the bronchi, wheezing and often dyspnoea

Extrinsic or atopic asthma is usually associated with a history of allergy and raised plasma IgE.

Intrinsic or non-atopic asthma may be precipitated by a variety of factors such as exercise, emotion and infection.

The role of radiology in Asthma

Normal chest X-ray during remissions.

During attack the chest X-ray may show:

Signs of hyperinflation with depression of the diaphragm and expansion of the retrosternal

air space.

During an asthmatic attack the lungs are hyperinflated, the diaphragms being and flattened.

During remission the chest normal

Chest radiographs: to exclude complications and associations with asthma

Consolidation Atelectasis with mucoid impaction, Pneumothorax, Pneumomediastinum, ABPA.

Role of HRCT

Characteristic CT findings

Bronchial dilatation Bronchial wall thickening

Mucoid impaction

Cylindric bronchiectasis

Centrilobular bronchiolar abnormalities such as tree-in-bud

Patchy areas of mosaic perfusion

Regional areas of air-trapping on expiratory scans

mild bronchial thickening and dilatation

HRCT during expiration demonstrates a mosaic pattern of lung attenuation in a patient with asthma. 

Chronic bronchitis Traditionally defined when cough and sputum

expectoration occurs on most days for at least 3 months of the year and for at least 2 consecutive years

cigarette smoking is responsible for 85% to 90%.

complications : Pulmonary emphysema superimposed infection or possibly bronchiectasis. cor pulmonale.

Chronic bronchitis Small poorly defined opacities are present throughout both lungs, producing the 'dirty chest

BronchiolitisCurrent pathologic classification includes

three main categories of bronchiolitis:

Cellular bronchiolitis, Bronchiolitis obliterans with intraluminal

polyps, Constrictive (obliterative) bronchiolitis

Causes of Cellular Bronchiolitis

Poorly defined centrilobular nodules and/or a combination of linear and nodular branching opacities (tree-in-bud sign).

Presence of poorly defined ground-glass centrilobular nodules

Axial CT image demonstrates diffuse centrilobular nodular and branching opacities (arrows) with tree-in-bud configuration.

Causes of Constrictive Bronchiolitis

Axial end-inspiratory HRCT scan is normal. B, Axial end-expiratory HRCT image shows multiple lobular foci of air-trapping . Coronal end-inspiratory (C) and end-expiratory (D) images provide better appreciation of the extent of air-trapping .

Collapse

Partial or complete loss of volume of a lung is referred to as collapse or atlectasis.

Mechanism of collapse

Relaxation or passive collapse: When air or increased fluid collected in

pleural space , lung tends to retract towards hilum.

Cicatrisation collapse Pulmonary fibrosis: Lung is abnormally stiff,

lung compliance is decreased and the volume of the affected lung is reduced.

Adhesive collapse Respiratory distress syndrome

surface tension of alveoli is decreased by surfactant. If this mechanism is disturbed, collapse of alveoli occurs, although the central airways remain patent

Resorption collapseIn acute bronchial obstruction the gases in the

alveoli are steadily taken up by the blood in the pulmonary capillaries and are not replenished, causing alveolar collapse.

Collapse seen in carcinoma of the bronchus.

Abrupt cut-off of the left main bronchus marked displacement of the right lung anteriorly and posteriorly across the midline

Total right lung collapse in a neonate. The patient was ventilated for respiratory distress syndrome and the cause of the total lung collapse was a mucus plug

Direct signs of collapse

Displacement of interlobar fissures

Loss of aeration

Vascular and bronchial signs

Indirect sign of collapse

Elevation of hemidiaphragm

Mediastinal displacement

Hilar displacement

Compensatory hyperinflation

Right Upper Lobe Collapse

Volume loss of the right upper lobe.

Right upper zone has become dense due to lobar collapse.

The volume loss has displaced the trachea which is PULLED to the right, and the horizontal fissure (arrow) has been PULLED upwards

Right upper lobe collapse. An example of right upper lobe collapse mimicking an apical cap of fluid (arrow).

Tight right upper lobe collapse. Note how the collapsed lobe (due to a central bronchogenic carcinoma) results in increased right paramediastinal density

On CT, the collapsed RUL is seen as a sharply defined triangular density bordered by the minor fissure laterally and the major fissure posteriorly

On computed tomography, the collapsed lobe appears as a triangular, enhancing structure, sharply marginated laterally by the minor fissure (solid arrows) and posteriorly by the major fissure (open arrow). B: On a more caudal image, the obstruction (arrow) of the lobar bronchus is demonstrated. C: Even more caudal, the collapsed lobe is flattened against the mediastinum

Left Upper Lobe Collapse

Left lower lobe has increased in volume to compensate volume loss and can be seen wrapping round the medial side of the collapsed upper lobe. This is known as the 'Luftsichel' (air crescent) sign .

PA and lateral chest radiographs in a patient with tight left upper lobe collapse and hyperexpansion of the left lower lobe. There is resulting hyperlucency (“luftsichel” sign) adjacent to the thoracic aorta.

Left Upper Lobe Collapse

Left Upper Lobe Collapse

Juxtaphrenic peak sign. A small triangular density (arrow) is seen in a left upper lobe collapse. The sign is due to reorientation of an inferior accessory fissure

Left Upper Lobe Collapse

Atypical left upper lobe collapse. The frontal radiograph demonstrates the inferior concave border of the collapsed lobe and resembles a right upper lobe collapse

On CT, the atelectatic LUL appears as a triangular or V-shaped soft tissue density structure that abuts the chest wall anterolaterally with the apex of the V merging with the pulmonary hilum

Right Middle Lobe Collapse

Minor fissure and lower half of the major fissure move close together.

Lordotic AP projection brings the displaced fissure into the line of the Xray beam, and may elegantly demonstrate right middle lobe collapse.

Since the volume of this lobe is relatively small, indirect signs of volume loss are rarely present.

On CT scans, the collapsed lobe is triangular or trapezoidal, and is demarcated by the minor fissure anteriorly

Middle lobe collapse. Collapsed lobe seen as a wedge-shaped structure, bordered by the minor (long arrows) and major (short arrows) fissures.

Lower Lobe Collapse

The pattern of collapse is similar for both lower lobes, which collapse caudally, posteriorly, and medially toward the spine.

On CT, the collapsed lower lobe appears as a wedged-shaped soft tissue attenuation structure adjacent to the spine.

Major fissure, which forms the lateral border of the lobe, is displaced

chest x-ray of RLL collapseTracheal deviation to the right

overall volume loss of the right hemithorax, compared with the left.

The mediastinum is therefore PULLED to the right.

RLL collapse

Left lower lobe collapse

The tracheal deviation to left.classical appearance of a 'double left heart

border,' or a 'sail sign' (orange). The second heart border (curved arrow) is due to the dense edge of the collapsed left lower lobe, which has been squashed into a triangle or sail shape.

PA (right) and lateral (left) chest radiographs in a patient with tight left lower lobe collapse. Note the triangular white opacity (black arrows) behind the heart obscuring the posteromedial left hemidiaphragm.

Left lower lobe collapse.

Lower lobe atelectasis. CECT demonstrates marked enhancement of the collapsed left lower lobe (arrowheads) and posterior basal segment of the right lower lobe (arrow) in a postabdominal surgery patient suspected of having pulmonary embolism

Rounded AtelectasisSymphysis of the visceral and parietal pleura,

and resultant infolding and entrapment of a peripheral portion of the underlying lung

3 to 5 cm in diameter

Most commonly located in the paraspinal region

Composed of a swirl of atelectatic parenchyma adjacent to thickened pleura

Round atelactasis

CT findings Rounded or wedge-shaped mass that forms an acute angle

with thickened pleura

Pleura is usually thickest at its contact with the contiguous mass

vessels swirling around and converging in a curvilinear

fashion into lower border of mass (comet tail sign)

Air bronchograms in the central portion of the mass

Homogeneous contrast enhancement of the atelectatic lung

Axial enhanced CT scan of the chest shows a nodular-area of increased density (blue arrow),associated with pleural thickening and pleural plaques (yellow arrows) consistent with asbestos-related pleural disease. Red arrow point to "comet tail" density that surrounds rounded atelectasis

Round atelactasis

THANK YOU

Distinguish Giant Bulla from Pneumothorax

Important for treatment plan

Differentiation can be difficult on conventional radiography; they can coexist

Expiratory chest radiograph may help delineating a visceral pleural line of pneumothorax

CT scan is the most accurate mean to differentiate the two diagnoses

"Double wall" sign described in cases with ruptured bulla causing pneumothorax (air outlining both sides of the bulla wall parallel to the chest wall)