Alveolar / Alveolar / Airspace lung Airspace lung

diseasediseaseAcute,chronic and ground Acute,chronic and ground

glass consolidation / glass consolidation / opacificationopacification

Jacques le RouxJacques le Roux03/02/201203/02/2012

Definition (air space Definition (air space disease)disease)

Disease process (fluid or cells) that Disease process (fluid or cells) that replaces the normal air spaces in the replaces the normal air spaces in the lunglung

Homogeneous opacity characterised by Homogeneous opacity characterised by little or no volume loss, little or no volume loss,

Effacement of pulmonary vessels Effacement of pulmonary vessels unlike ground glass opacitiesunlike ground glass opacities

And if airways remain air filled you see And if airways remain air filled you see air bronchogramsair bronchograms

AIR SPACE DISEASE (ALVEOLAR LUNG DISEASE)

•Acute and chronic consolidation

•Ground glass opacity

•Anatomy (HRCT)

•Pathology and complications

•Approach •Diseases (acute and chronic) consolidation•Clinical• Lab• Options: diseases on CXR •Ground glass opacity - Approach - HRCT (expiration and inspiration)

ANATOMY ON HRCT

AIRSPACE (ALVEOLI)Distal to term bronchioli are the sec. pulm. lobule (best seen on CT in lung periphery)contains:

•Acini –with the alveoli and respiratory bronchioli •Pores of Kohn connect the alveoli•Channels of Lambert connect alveoli with the bronchi

Acini not seen on CT

ALVEOLAR INTERSTITIUM•Peribroncho vasc. interstitium runs from hilum to periphery of lung•It becomes the centrilobular interst in the lobule and contains the art. and bronchioli•At the periphery is the interlob. septa with vein and lymphatics

On CT you see:- arteries and veins but not centrilob. bronchioli and lymphatics

Normal HRCT lobular anatomy

PATHOLOGY

Air space disease can be:1 Alveolar2 Interstitial3 Mixed (overflow of disease from interstitium)

NB - ALVEOLI CAN BE FILLED WITH: (The consolidation)

•Serous fluid: cardiogenic and non cardiogenic edema•Blood: pulm. hemorrhage: - vascilitis (eg Wegener’s) - PE•Pus: pneumonia•Proteins: alveolar proteinosis•Malignant cells - BAC - Lymphoma•Calcium: alveolar microlithiasis

COMPLICATIONS

ACUTE•Pleural effusion•Empyema with or without BR. pleural fistel•Lung abcess•Atelectasis (Broncho PN)

GROUND GLASS OPACITY (Mainly a HRCT term)

•Sign of acute disease•Can Δ early changes before consolidation is present•Means: -hazy increase in lung density (high att)

-CAN SEE VESSELS THROUGH THE HAZE

If reticulations are superimposed, use term ‘crazy paving’or honey combing

CHRONIC•PAH•Bronchiectasis (traction)•Emphysema (irregular) - in area of fibrosis

Acute and chronic air space Acute and chronic air space consolidationconsolidation

AIRSPACE DISEASE (CONSOLIDATION)ACUTE1. Pneumonia (bact, viral, PCP, mycoplasma)2. ARDS, AIP (Ideopatic ARDS – Hamman Rich)3. Hemorrhage (PE)4. Aspiration5. Acute eosin. PN (Löffler)6. Radiation

CHRONIC1. Tumors - BAC - Lymphoma 2. Inflam - TB, Fungi - COP (BOOP) - with eosinophilia:

- chronic eosinophilic PN - ABPA (aspergillosis) - Drugs (penicillin) - Churg-Strauss (asthma + granulomas)

3. Vascular - pulm renal syndromes eg. Good Pasture, H-S Purpura, Wegener4. Other

• Alveolar sarcoidosis• Interst. Pneumonias (UIP, DIP, NSIP)• Chronic hypersensit PN (Farmer Lung)• Lipoid PN (laxatives, eye drops)

CLINICAL (IMPORTANT)

ACUTE•Dyspnea•Purulent sputum•Fever•Bronchial breathing

LAB:•Immunocompromised patient eg AIDS•Sputum•Lung func tests•Sarcoid (↑ ACE and calcium)•Wegener (ANCA)•Good pasture (Anti-GBM)•Other: - Bronchoscopy – lavage, biopsy

CHRONIC•Dyspnea•Dry cough•Finger clubbing•Dry crepitations

A. NON SPECIFIC – Does not tell cause SIGNS OF CONSOLIDATION (HRCT can’t tell you more than CXR)•Opacities - fluffy hazy - margin indistinct (except if process is against a fissure) - tend to merge into one another•Air bronchogram – there is air in bronchi and exudate around them (black branching tubular structures)•Silhouette sign (2 objects in contact with each other and must have same density) - margin will be obscure•No blood vessels in opacity•No volume loss – structures don’t move eg fissures, diaph, mediastinum•Spine sign (lat film)

CXRTHE APPROACH

USING SILHOUETTE SIGN ON FRONTAL CXR

Structure That Is No Longer Visible Disease LocationAscending aorta Right upper lobeRight heart border Right middle lobeRight hemidiaphragm Right lower lobeDescending aorta Left upper or lower lobeLeft heart border Lingula of left upper lobeLeft hemidiaphragm Left lower lobe

On a Normal CXR: - You see no bronchi – walls too thin and air on both sides - What you see are blood vessels

* Consolidation, example ARDS ,pulm oedema will clear quickly within hoursBacterial PN will clear within 10 daysSo important do a follow-up CXR

B. MORE SPECIFIC (MIGHT LIMIT THE ΔΔ)

CONSOLIDATION (CXR)

DIFFUSE•PN /oedema•ARDS(Bat-wing)•Hemorrhage

LOBAR•PN (Strep) - Air bronchogram - No vessels

RETICULAR/NOD•Viral•Mycoplasma•PCP

PATCHY•Broncho PN (Staph+ Mycopl) - No bronchogram - Collapse (vol. loss) (bronchi blocked)

OTHER1. Bulging fissures – Klebsiella2. Round PN (H.Influenza) – Child (no pores of Kohn, canals of Lambert)3. Cavity with mass – Aspergilloma4. Mass with finger shadows – Acute bronchopulmonary aspergillosis (ABPA)5. Solitary nodule – Criptococcus (AIDS)6. Multiple nodules – Histoplasmosis7. Cavities – Post prim TB / pseudomonas8. Pneumotocele – Staph, PCP9. Aspiration – Lower lobes (bacteroides)10. Mycoplasma – Signs of both bact and virus (patchy Bronch PN and reticular)

ExamplesExamples

DIFFUSECARDIOGENIC PULM EDEMA•Bilat perihilum airspace disease (bat-wing)•↑Heart•Cardiogenic pulm edema due to eg CHF•Usually pleural effusions•Kerley lines•Peribronch cuffing

NON CARDIOGENIC EDEMA (ARDS)•Bilat perihilum airspace disease (bat-wing)•Normal heart•Non cardiac. pulm edema due to eg septic shock•Usually no pleura eff. or Kerley lines

OTHER SIGNS OF CARDIOG. PULM EDEMA

Kerley B - Interlob septa - Near pleura - Short (1-2cm)

Kerley A - Broncho art. bundle - Near hilum - Long 6cm

Peribronch. cuffing - Fluid aroud bronchi - walls look thicker

LOBAR – STREPTOC. PNEUMONIA

RML PNEUMONIACXR (PA) - Homogeneous consolidation - Silhouette sign Lat - Major, minor fissures clearly seen

CT - Air bronchogram (better seen centrally)

LOBAR PN

RUL PN•Homogeneous consolidation•Air bronchogram centrally•Minor fissure – demarcate lesion (Fissures bound lobar PN)

LINGULAR PN (LUL)•Air bronchogram•Silhouette sign (left heart border)

BRONCHO PN - STAPH

•Patchy consolidation, moving centrifugally•Lung segments are not bound by fissures (only lobes)

•No air bronchogram because exudate fills bronchi as well as airspaces

INTERST PN– RETICULAR PATTERN

PCP IN PATIENT WITH AIDS•Disease starts as an interst (reticular) disease, perihilum and spreads to airspace•No effusion, or adenopathy•Δ sputum methanamine silver staining

ROUND PNEUMONIA – H. INFLUENZA

•Child with fever and a mass

TB

PRIMARY

CHILD - Usually ipsilat adenopathy - If consolidation – upper lobe

ADULTS - Large unilat effusion

POST PRIM•Cavitation common•Classic bilat upper lobes

- upper lobe (apical, post segments)- or lower lobes (sup segments)

•Transbronchial spread eg upper lobe to opposite lower lobe is common•Healing causes fibrosis, traction bronchiectasis

ASPIRATION PN – Anaerobic organisms (Bacteroides)

Lower lobes – R more affected(R bronchus short,straight, wide)

•ACUTE aspiration gives airspace disease – in stroke patient

•CHRONIC aspiration cavitation

THE SPINE SIGN – RLL PN

CXR (PA)•R LL PN – Not so obvious, but hemidiaphragm not clearly definedCXR (LAT)•Normal vertebrae bodies get darker as you go down (less tissue for beam to penetrate)•Lower throracic vertebrae whiter – the spine sign for R LL PN

Broncho PN – STAPH•Patchy consolidation L and R•Abcess and cavity formation

PN - Pseudomonas - L Apical-Cavity - Bronchoscopy revealed org

PN – Mycoplasma (sputum Δ)•Diffuse reticular interst markings•Bilat lower lung zone airspace disease

PRIM TB•RUL consolidation•Hilum and right paratracheal nodes

ASPERGILLOMA•History of TB•Mass with crescent of air (Monod sign) and pleural thickening – RUL

Bulging of minor fissure - Klebsiella

CMV - patchy consolidation - nodules in interstitium

BAC (chronic)BAC (chronic)

Consolidation and ground-glass present

? Sign? Sign CT angiogram sign CT angiogram sign

? 3 Associations ? 3 Associations

1) BAC1) BAC2) lymphoma2) lymphoma3) infective PN3) infective PN

GROUND-GLASS OPACITY

LUNG OPACITY ( ↑ LUNG ATTENUATION ON HRCT )

CONSOLIDATION

• BRONGOGRAM• NO VESSELS

GROUND GLASS OPACITY (HAZY LUNG - ↑ ATT, SEE BLOOD VESSELS)

NO RETICULATIONS(ACTIVE DISEASE 80%)WITH RETICULATION

SUBPLEURALPOST LOWER LOBES

•IPF(60%)•ASBESTOSIS

HONEYCOMBING

FIBROSIS LIKELY(95%)

CRAZY PAVING

ACTIVE DISEASE LIKELY

•ALVEOLAR PROTEINOSIS•ARDS•PULM. HEMORRHAGEUPPER LOBE

•SARCOIDOSIS

DIFFUSE

•INTERST.PN (UIP, DIP, AIP)•PCP•CMV•HEMORRHAGE•OEDEMA

NODULAR - centrilobularPERIPHERAL PATCHY

•EOSINPHELIC PN

NB NB Mosaic attenuation – areas of ↓ att vs MOSAIC PERFUSION• Sign of vascular obstruction or airway obstruction (usually)• ↓att on inspiratory scan – call it mosaic perfusion – vessels appear smaller (difficult to see)• ↓att on expiratory scan – call it air trapping

NODULES [will be done at later stage]

•Micronodule < 3 mm•Small < 1 cm•Large 1-3 cm•Mass > 3 cm

•Centrilobular interst contains- bronchioli – don’t see normally on HRCT- artery – you see

•Nodules can be 1. Alveolar (centrilobular) – air space disease 2. Interstitial

HRCT OF CENTRILOB NODULES (AIR SPACE)

Centrilobular interstitum•Art and bronchioli are enlarged but smooth- usually due to fluid•Art and bronchioli show a nodular pattern due to other causes ,infection

SMALL NODULE DISTRUBUTION

( HEMATOGENEOUS DISEASE)• MILIARY TB, FUNGI, METS• SARCOID

RANDOM

PERILYMPHATIC

(NEAR PLEURA AND FISSURES)• PN CONIOSIS• SARCOID• LYMPHANGITIS• LYMPHOMA• LIP

NO TREE IN BUD

( SIGN OF BRONCHI AND VASC. DISEASE- BRONCHI AND ART SMOOTH DILATED)

• FLUID -PUM EDEMA - HIPERSENS PN - BOOP

****CENTRILOBULAR NODULES5 – 10 mm from pleura

TREE IN BUD

(SIGN OF BRONCHIOLAR DISEASE - CENTRAL BRONCHI DILATED AND BRANCHING)

• USUALLY BY PUS (INFECTION) - TB(ACTIVE) - Broncho PN - MYCOPLASMA

• MUCUS - ASTHMA

ExamplesExamples

PULM. HEMORRHAGE

Combination of

•Consolidation- no vessels- air bronchograms

•Ground-glass opacity vessels - Sign of acute disease - Lung hazy (↑ att) - See vessels

BRONCHOPNEUMONIAHRCT (Signs)

A.Centrilobular nodules

B. Tree-in-bud - dilated centrilobular bronchioli - can be filled with pus, fluid or mucus - there are peribronchiolar inflam. (walls appears thick) - bronchiectasis (signet ring)

C. Pathology slice

PCP (PNEUMOCYSTIS CARINII PNEUMONIA) - JIROVECI

TB

ACUTE INTERSTITIAL PNEUMONIA (HAMMAN RICH)(IDEOPATHIC ARDS)

CXR and HRCT•Peripheral ground-glass and consolidation opacities like ARDS•But more lower lobe disease

•Fulminant lung disease (> 50% fatal)•Occurs in previously healthy people (> 40 years)•Present with signs of ARDS with rapid deterioration suggesting PN-like disease

SIMPLE EOSINOPHILIC PNEUMONIA (LÖFFLER)

•Usually patient with asthma and peripheral eosinophilia (blood)

CXR - Bilat. peripheral airspace disease

HRCT - Periph. ground-glass opacity with reticulation – upper lobes

PULM. ALVEOLAR PROTEINOSIS

•Rare (males 20-40 years)•Ass. with silica dust (sandblasters) and ↓ immune patient•↑ surfactant (lipoprotein material) accumulate in airspaces

CXR - Bilat. airspace opacities

HRCT - Crazy paving (classic) - is a combination of ground-glass opacity and interlobular thickening

- also seen in ARDS and pulm. hemorrhage

BOOP (COP)

Inflam. of respiratory bronchioli with obstruction by plugs of granulation tissue(bronchiolitis obliterans) with organizing pneumonia

CAUSE: - unknown - possible : - radiation - amiodarone - auto immune diseasesHRCT:

•Peripheral triangular patchy areas of consolidation (typical)•Classic – ATOLL sign

- is an area of ground-glass surrounded by a ring of ↑ density (consolidation)

HIPERSENSITIVITY PNEUMONITIS (EXTRINSIC ALLERGIC ALVEOLITIS)eg FARMERS LUNG (ORGANIC DUST – HAY)

HEADCHEESE SIGN (Typical) – looks like a type of sausage• A type of mosaic attenuation manifested by a combination of:1. Patchy ground-glass opacity – you see bloodvessels2. Patchy consolidation – no bloodvessels, air bronchograms possible3. Mosaic attenuation – areas of ↓ att

• Sign of vascular obstruction or airway obstruction (usually)• ↓att on inspiratory scan – call it mosaic perfusion – vessels appear smaller (difficult to see)• ↓att on expiratory scan – call it air trapping

Difficult to ΔΔ between pulmonary edema(cardiogenic or non cardiogenic (ARDS) on HRCT)Both give pulm. alveolar edema(ground-glass opacity)

• Cardiogenic - more smooth septal thickening (Kerley lines) - perihilar ground-glass opacity - ↑ heart

• Non cardiogenic - more peripheral ground-glass opacity - normal heart

PULMONARY EDEMA

PAH (complication)

SUMMARY• CXR will tell you there is a consolidation (airspace disease) but not the cause, (no blood vessels ,air bronchograms, silhouette sign)

• If you were given one investigation to detect the cause for ground-glass opacity- Non invasive : HRCT- Invasive : Lung biopsy

*NB! NB! Ground-glass = area of increased density , see vessels, acute changes

Mosaic attentuation = areas of decreased density / attentuation sign of vascular obstruction or airway obstruction

On expiratory scan decreased att = air trapping

Mosaic perfusion = area of decreased attentuation on inspiratory scan vessels appear smaller, difficult to see thinking chronic PE

References

1. Herring W. Learning Radiology, Mosby, 20072. Webb WR. HRCT Of The Lung 4th ed. Lippincott, 20093. Brant W. Helms G. Fundamental Of Diagnostic Radiology, Lippincott. 20074. Mayberry JP. Thoracic Manifestations Of Auto Immune Diseases : Radiographic And HRCT Findings, Radiographic 2000, 20: 1623-16355. AL-Tubaikh J. Internal Medicine, An Illustrated Radiological Guide, Springer, 20106. Gurney. Diagnostic Imaging, Chest, 2007.