Radiology Pathology Clinical 1 11/7/2018 Role of HRCT Diagnosis - - PDF document

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Radiology Approach to ILD

Brett M. Elicker, MD University of California, San Francisco

Radiology Pathology Clinical

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Role of HRCT

• Diagnosis
• Fibrosis vs. inflammation
• Next step in management
• Response to treatment

Confidence in diagnosis

CT = diagnostic pattern CT + clinical = diagnostic pattern CT = nonspecific

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Clinical Context

History Diagnosis History Diagnosis Bird/mold exposure Hypersensitivity pneumonitis History Diagnosis Bird/mold exposure Hypersensitivity pneumonitis Smoking Respiratory bronchiolitis History Diagnosis Bird/mold exposure Hypersensitivity pneumonitis Smoking Respiratory bronchiolitis Connective tissue disease Follicular bronchiolitis History Diagnosis Bird/mold exposure Hypersensitivity pneumonitis Smoking Respiratory bronchiolitis Connective tissue disease Follicular bronchiolitis Acute symptoms

• nly

Viral infection

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End stage IPF

Markedly reduced TLC and DLCO

End stage constrictive bronchiolitis

Inspiration

Markedly reduced FEV1

Expiration

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HRCT may show reduced sensitivity for:

• Small airways diseases

– Constrictive broncholitis – Hypersensitivity pneumonitis – Asthma

• Emphysema
• Pulmonary hypertension

Fibrosis vs. Inflammation

No GGO‐ fibrosis GGO‐ inflammation GGO‐ fibrosis

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HRCT guides further work-up

Bronchoscopy Sputum VATS

HRCT: follow-up after tx

• Disease that is below the

threshold of PFTs

• Mixed disease (e.g. airways

and fibrosis)

• Multi-compartmental disease

(e.g. lung and pleura)

• Acute symptoms

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Interpreting HRCTs

• 1. What is the most significant finding?
• 2. What is the distribution within the lungs?
• 3. Are there ancillary findings that increase

specificity?

• 4. Is there helpful clinical information?

Case #1: What is the most significant finding?

Honeycombing Irregular reticulation Traction bronchiectasis

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Case #1: What is the distribution in the lung?

Subpleural Basilar

Case #1: Are there are associated findings that increase specificity?

Associated finding (in setting of fibrosis) Disease Associated finding (in setting of fibrosis) Disease Mosaic perfusion and/or air trapping Hypersensitivity pneumonitis Associated finding (in setting of fibrosis) Disease Mosaic perfusion and/or air trapping Hypersensitivity pneumonitis Diffuse nodules Hypersensitivity pneumonitis, sarcoidosis Associated finding (in setting of fibrosis) Disease Mosaic perfusion and/or air trapping Hypersensitivity pneumonitis Diffuse nodules Hypersensitivity pneumonitis, sarcoidosis Ground glass opacity or consolidation Connective tissue disease, hypersensitivity pneumonitis, drugs Associated finding (in setting of fibrosis) Disease Mosaic perfusion and/or air trapping Hypersensitivity pneumonitis Diffuse nodules Hypersensitivity pneumonitis, sarcoidosis Ground glass opacity or consolidation Connective tissue disease, hypersensitivity pneumonitis, drugs Cysts Connective tissue disease, smoking (i.e. desquamative interstitial pneumonia)

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Case #1: Is there helpful clinical information?

Clinical clue Disease Clinical clue Disease Inhaled exposure Hypersensitivity pneumonitis, pneumoconiosis Clinical clue Disease Inhaled exposure Hypersensitivity pneumonitis, pneumoconiosis Drug exposure Drug toxicity Clinical clue Disease Inhaled exposure Hypersensitivity pneumonitis, pneumoconiosis Drug exposure Drug toxicity Clinical or physical exam findings of connective tissue disease (CTD) Rheumatoid, scleroderma, myositis, lupus, Sjogren’s, mixed CTD Clinical clue Disease Inhaled exposure Hypersensitivity pneumonitis, pneumoconiosis Drug exposure Drug toxicity Clinical or physical exam findings of connective tissue disease (CTD) Rheumatoid, scleroderma, myositis, lupus, Sjogren’s, mixed CTD Idiopathic Idiopathic pulmonary fibrosis, hypersensitivity pneumonitis, sarcoidosis

Case #1: summary and diagnosis

• 1. Fibrosis with

honeycombing

• 2. Subpleural/basilar

distribution

• 3. No associated findings
• 4. No clinical clues

Usual interstitial pneumonia Idiopathic pulmonary fibrosis

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Usual interstitial pneumonia Pathology Radiology

Histologic Pattern Idiopathic Clinical Syndrome Associated Diseases Usual interstitial pneumonia Idiopathic pulmonary fibrosis Connective tissue disease (CTD), drugs, asbestosis Nonspecific interstitial pneumonia (NSIP) Idiopathic NSIP CTD, drugs, hypersensitivity pneumonitis (HP) Desquamative interstitial pneumonia (DIP) Idiopathic DIP Smoking, CTD, drugs, toxic inhalations Organizing pneumonia (OP) Cryptogenic OP CTD, drugs, infections, chronic eosinophilic pneumonia, HP Constrictive bronchiolitis (CB) Idiopathic CB Post‐viral, CTD, drugs, graft vs. host disease, lung transplant rejection Diffuse alveolar damage Acute interstitial pneumonia Infection, aspiration, trauma, sepsis, pancreatitis, etc. Histologic Pattern Idiopathic Clinical Syndrome Associated Diseases Usual interstitial pneumonia Idiopathic pulmonary fibrosis Connective tissue disease (CTD), drugs, asbestosis Nonspecific interstitial pneumonia (NSIP) Idiopathic NSIP CTD, drugs, hypersensitivity pneumonitis (HP) Desquamative interstitial pneumonia (DIP) Idiopathic DIP Smoking, CTD, drugs, toxic inhalations Organizing pneumonia (OP) Cryptogenic OP CTD, drugs, infections, chronic eosinophilic pneumonia, HP Constrictive bronchiolitis (CB) Idiopathic CB Post‐viral, CTD, drugs, graft vs. host disease, lung transplant rejection Diffuse alveolar damage Acute interstitial pneumonia Infection, aspiration, trauma, sepsis, pancreatitis, etc.

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UIP: clinical clues

Rheumatoid Drug Asbestosis IPF

UIP Criteria

Raghu et al. Am J Respir Crit Care Med. 2018; 198: e44.

Confidence in IPF Category Criteria Distribution High (≥95%) UIP

• Honeycombing
• Traction bronchiectasis
• Lack of atypical features

Subpleural and basilar Intermediate to high (60‐ 90%) Probable UIP

• Reticulation
• Traction bronchiectasis
• No honeycombing

Subpleural and basilar Intermediate (?) Indeterminate for UIP

• Mild reticulation
• No traction bronchiectasis

OR

• Mild ground glass opacity

Subpleural and basilar Low (25%) Suggestive of alternative diagnosis

• Features atypical for UIP

NOT subpleural or basilar

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Do NOT overall UIP!

• Honeycombing mimics
• Incorrect distribution
• Presence of atypical features

Honeycombing

• Honeycombing features

– Air density – Round with fairly thick wall – Always involves subpleural lung – Single or multiple layers – Associated sign(s) of fibrosis

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Honeycombing mimics

Traction bronchiectasis Cystic lung disease Emphysema

Sjogren’s disease: nonspecific and lymphoid interstitial pneumonia

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Distribution

Axial Coronal

Associated findings

Bilateral in ≥3 lobes

• Mosaic perfusion

(inspiration)

• Air trapping

(expiration)

• Nodules
• Ground glass opacity
• Consolidation
• Cysts

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What diseases/patterns may mimic IPF on HRCT?

• Nonspecific interstitial pneumonia (NSIP)
• Desquamative interstitial pneumonia
• Hypersensitivity pneumonitis

Nonspecific interstitial pneumonia

Subpleural sparing 7 years later

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Desquamative interstitial pneumonia

5 years before

Hypersensitivity pneumonitis

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Unknown case

• Head cheese is in fact not a

cheese, but rather a terrine made

• f meat taken from the head of a

calf or pig (sometimes a sheep

• r cow) that would not
• therwise be considered

appealing.

Headcheese

Headcheese sign

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Ground glass

• pacity
• Changes below resolution of

CT

• Compartments of lung

effective

– Alveolar – Interstitial – Mixed

• Broad differential diagnosis
• Acute vs. chronic symptoms

Mosaic perfusion

• Geographic areas of lucent

lung

• Reflects areas of reduced

perfusion

• Causes

– Airways disease – Vascular disease

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Mosaic perfusion (lucent lung abnormal)

Air trapping Vessel size discrepancy Very geographic Insp. Exp.

Headcheese sign

• Three components

– Infiltrative (ground glass) – Obstructive (mosaic perfusion) – Intermediate density lung (normal)

• Both in significant

amounts

• Diagnosis usually HP

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Hypersensitivity Pneumonitis

*Headcheese courtesy of Oscar Meyer

Radiology Approach to ILD

Brett M. Elicker, MD University of California, San Francisco