3rd Seed Program / Shanghai 2015

Idiopathic Interstitial PneumoniasClassification and Imaging Features

Gerald F. Abbott MD

Harvard Medical School / Massachusetts General Hospital

Interstitial Pneumonias

Group of diffuse lung diseases

Varying degrees of

inflammation and fibrosis

Reactions to lung injury

Specific histologic patterns

Idiopathic or associated

with specific diseases:

Collagen vascular disease

Infection

Smoking

Drugs

Pulmonary

Interstitium

Idiopathic Interstitial PneumoniasClassification

American Thoracic Society ATS

European Respiratory Society ERS

2002 Multidisciplinary effort

Consensus Statement / Classification

2013 Revised Classification

Idiopathic Interstitial PneumoniasClassification / 2002 ATS-ERS

Morphologic Pattern Idiopathic Syndrome

Usual Interstitial Pneumonia UIP

Idiopathic pulmonary fibrosis IPF

Nonspecific IP pattern NSIP Idiopathic NSIP NSIP

Desquamative IP pattern DIP Desquamative IP DIP

Respiratory bronchiolitis RB Respiratory bronchiolitis ILD RBILD

Organizing pneumonia OP Cryptogenic organizing pna COP

Diffuse alveolar damage DAD Acute IP AIP

Lymphoid IP pattern LIP Idiopathic LIP LIP

Category Morphologic pattern Clinical-Rad-Path Dx

Chronic fibrosing IP UIP IPF

NSIP Idiopathic NSIP

Smoking-related IP DIP DIP

RB RBILD

Acute / Subacute IP OP COP

DAD AIP

Rare entity LIP Idiopathic LIP

Idiopathic Interstitial PneumoniasRevisions / 2013 ATS-ERS

Idiopathic Interstitial Pneumonias Relative Frequency

PATTERN FREQUENCY

UIP 40%

NSIP 20%

DIP 20%

RB

OP 10%

DAD 10%

LIP Rare

Usual Interstitial Pneumonia UIPMost common IIP (50%)Irreversible fibrosisIdiopathic = IPFConnective tissue disease

Drugs, Asbestosis

Usually males > 50 yearsDyspnea, dry cough

Survival: 40% at 5 yearsNot steroid-responsive

Marked fibrosis

Fibroblastic foci

Patchy involvement

Architectural distortion

Honeycombing

(subpleural / paraseptal)

Usual Interstitial Pneumonia Pathology

Fibroblastic foci

Temporal heterogeneity

Simultaneous presence of

Old fibrosed lesions

Subacute fibroblastic foci

New inflammation

Spatial heterogeneity

Uneven distribution of findings

Usual Interstitial Pneumonia Pathology

UIP PatternSubpleural, basal

predominance

Reticulation

Honeycombing

+/- Traction Bronchiectasis

ATS/ERS/JRS/ALAT Statement: Idiopathic Pulmonary Fibrosis: Evidence-based Guidelines for Diagnosis and Management. AJRCCM, 2011 Mar 15;183:788-824

Usual Interstitial Pneumonia Diagnostic Imaging Criteria

Usual Interstitial Pneumonia UIPReticular pattern

Symmetric

Linear, irregular

Peripheral

Bibasilar

Irregular interface along pleura

Traction bronchiectasis

Advanced UIP Coarse reticulation Loss of volume

Early UIP Fine / medium

reticulation

Baseline 3 years later

HoneycombingAdvanced fibrosis

Cystic air spaces 3mm to 3cm

Thick, clearly defined walls

Multi-tiered or single row

Peripheral, subpleural

Strongest CT indicator of UIP

Poor median survival: 2.1 years

Usual Interstitial Pneumonia Complications

Lung Cancer5-15%

Infection

Acute Exacerbations

Common IIP

M = F / 40-50 years old

Better survival than UIP

Associated diseases

Collagen vascular disease

Environmental exposures

Drug toxicity

Cigarette smoking?

Nonspecific Interstitial PneumoniaNSIP

Inflammation

Fibrosis

Spectrum: cellular to fibrosing process

Spatial and temporal homogeneity

Uniform interstitial involvement

No Honeycombing or fibrotic foci

Nonspecific Interstitial PneumoniaPathology

Nonspecific Interstitial PneumoniaImaging

Ground-glass opacity

Reticulation

Relative subpleural sparing 43%

Peripheral, basilar predominant

Rare Honeycombing

Better prognosis than UIP

Steel wool

Nonspecific Interstitial PneumoniaImaging

Ground-glass opacity

Reticulation

Relative subpleural sparing 43%

Peripheral, basilar predominant

Rare Honeycombing

Better prognosis than UIP

Steel wool

Kligerman et al. Radiographics. 2009;29:73-87.

NSIP Imaging

2000 2002

NSIP – Follow-up CT ImagingSome will improve with steroids

2004 2010

NSIP – Follow-up CT ImagingSome will progress to fibrosis

NSIP HP

LIP DIP/RB-ILD

UIP

Nonspecific Interstitial PneumoniaOverlapping imaging features

Smoking-related Lung diseases

Respiratory Bronchiolitis RB

RB-Interstial Lung Disease RB-ILD

Desquamative interstitial pneumonia DIP

Idiopathic Pulmonary Fibrosis IPF ?

(Smoking is a recognized risk factor for IPF)

Cigarette smokers

Respiratory bronchioles

Histology:

Inflammation, fibrosis

Pigmented macrophages

HRCT:

Centrilobular ground-glass nodules

Patchy ground-glass opacity

Upper lobes

DDx: Hypersensitivity pneumonitis

Respiratory Bronchiolitis

Respiratory Bronchiolitis Pathology

Bronchiolocentric

Pigmented macrophages

“Dusty brown” macrophages

Peribronchiolar fibrosis

Emphysema

Centrilobular ground-glass nodules

Patchy ground-glass

Upper lobes

Emphysema ±

Respiratory Bronchiolitis Imaging

Symptomatic patients

Centrilobular nodules

Ground glass

Emphysema

Air trapping

Respiratory Bronchiolitis Interstitial Lung Disease

RB-ILD

Desquamative interstitial pneumoniaPathology

Diffuse involvement

Homogenous

Alveolar septal thickening

Macrophage accumulation

Desquamative interstitial pneumoniaImaging

Basal, peripheral predominanceGround-glass

Reticulation

Cysts

Emphysema

Organizing PneumoniaResponse to Lung Injury

Common pattern

Universal response to lung injury

50% idiopathic (cryptogenic)

Associated disease:

Connective tissue disease

Drug toxicity

Infection

Immunologic disorders

Clinical:

Low-grade fever, dyspnea, cough

Organizing Pneumonia PathologyOrganizing fibroblastic tissue

Fibroblasts and myofibroblasts

Form plugs of spindle-shaped cells

(Masson bodies) in alveolar ducts

and alveoli

Bronchiolar obstruction

Patchy distribution

Consolidations

Bilateral 90-95%

Peripheral / Peribronchial

10% Focal, Unilateral

May be migratory 11-24%

Associated signs:

Reverse Halo sign

Atoll sign

Organizing Pneumonia Imaging

Organizing Pneumonia Reverse Halo Sign

Central ground-glass opacity

Surrounding ring of consolidation

Reverse halo with incomplete ring

of consolidation

Resembles an atoll in Pacific ocean

Atoll: top of submerged mountain volcano.

low islands encircling a seawater lagoon.)

Organizing Pneumonia Atoll Sign

Rare pattern

Rapid respiratory failure

60-90% mortality

Pathology

Diffuse Alveolar Damage

3 phases:

Exudative

Proliferative

Fibrotic

Acute Interstitial PneumoniaAIP

Ground glass 53% of parenchyma

Consolidation 25% of parenchyma

Septal thickening 89%

Traction bronchiectasis

Architectural distortion

Radiology 1999; 859-863

Acute Interstitial PneumoniaImaging

Acute Interstitial Pneumonia

Lymphoid Interstitial PneumoniaLIPRare pattern

Benign lymphoproliferative disorder

Peribronchiolar lymphocytes & plasma cells

Age: 50 years & children with AIDS

Cough, dyspnea

Autoimmune disease / Immunodeficiency

Associated entities:

Sjogren syndrome, AIDS,

Primary biliary cirrhosis, Multicentric Castleman Disease

Lymphoid Interstitial PneumoniaImaging

Diffuse distribution

Ground-glass opacity

Centrilobular nodules

Basal reticulation

Thin-walled cysts 70%

Airway obstruction

Idiopathic Interstitial PneumoniasMulti-disciplinary Diagnosis

58 cases of suspected Idiopathic Interstitial Pneumonia

Independent review followed by

clinical-radiologic-pathologic consensus

Consensus review caused alteration of:

53% of radiologic diagnoses

34% of clinicial diagnoses

19% of pathologic diagnoses

Flaherty et al. Am J Respir Crit Care Med. 2004; 170:904-910.

3rd Seed Program / Shanghai 2015

Idiopathic Interstitial PneumoniasClassification and Imaging Features

Gerald F. Abbott MD

Harvard Medical School / Massachusetts General Hospital