Approach to CT of diffuse lung disease

Hiroto Hatabu, M.D., Ph.D, F.A.C.R.

Professor of Radiology, Harvard Medical School

Medical Director, Center for Pulmonary Functional Imaging

Brigham and Women’s Hospital

10th Taishou-ku Rinshou Gazou Kenkyukai

August 5, 2017, Osaka, Japan

Case 1

Case 2

Case 3

Case 4

Case 5

Case 6

Expiratory HRCT

Diffuse Lung Disease

Present

Or

Not Present

Diffuse Lung Disease

Distribution,

distribution

and distribution!!

Distribution

• Upper, middle, lower lung areas

• Peripheral or central

• Secondary pulmonary lobule

Secondary Pulmonary Lobule

• Fundamental unit of lung structure

marginated by connective tissue septa

(William Snow Miller, 1947)

• Can be seen by HRCT (Thin-section CT)

• Useful for making accurate diagnosis

Pulmonary Acinus

• Smaller than the secondary pulmonary lobule

• Distal to terminal bronchiole

• 6-10 mm in diameter

• 3-24 acini make secondary pulmonary lobule

Copyright ©Radiological Society of North America, 2006

(Webb, W. R. Radiology 2006;239:322-338)

Secondary Pulmonary Lobule

Secondary Pulmonary Lobule

Secondary Pulmonary Lobule

• Centrilobular structure

• Lobular parenchyma

• Interlobular septa and septal structure

Interlobular Septa and

Septal Structure

• Interlobular septa (Connective tissue)

• Pulmonary veins

• Pulmonary lymphatics

Centrilobular Structure

• Plmonary artery

• Bronchiolar branches

• Lymphatics

• Supporting connective tissue

Lobular Parenchyma

• Alveoli and associated pulmonary capillary

bed

• “Septal fibers”; connective tissue stroma,

fine network of very thin fibers within the

alveolar septa

Secondary Pulmonary Lobule and Disease

Processes

• Airway spread --- Infection

• Disease of lymphatic tract --- Pulmonary

edema, lymphangetic spread of tumors,

lymphoma, sarcoidosis

• Disease of interstitium --- UIP

• Hematgenous spread --- Metastasis

Lymphatic System

Centrilobular

Diffuse Panbronchiolitis (DPB)

The First Question

Is this IPF/collagen vascular disease/

asbestosis/ (NSIP)?

IPF/collagen vascular disease/(asbestosis)?

• Peripheral and basilar

• Honeycoming

• Decreased lung volume unless associated

with emphysema

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Idiopathic Pulmonary Fibrosis

• The most common interstitial lung disease,

accounting for 20 –25% of diffuse lung

diseases.

• Histologic diagnosis based on presence of

temporal and spatially heterogenous

interstitial fibrosis and inflammation.

Idiopathic Pulmonary Fibrosis

• Poor prognosis with median survival less

than 5 years.

• Complications include accelerated

progression, lung cancer and secondary

infection.

Useful Patterns

• Nodular

• Linear (lymphatic system)

Not Useful Patterns

• Reticular

• Reticulo-nodular

• I do not know what I am talking about!

Nodular

Nodular (fine)

• Miliary tuberculosis

• Metastasis

• Miliary sarcoidosis

Nodular (middle size or larger)

• Metastasis

• Metastasis

• Metastasis

Linear (lymphastic system)

• Pulmonary edema

• Sarcoidosis

• Lymphangitic spread of tumor

• Lymphoproliferative disorders

Centrilobular (tree-in-bud)

• Airway-related

• Most likely infection or

inflammation

• I do not know what it is,

however, it is probably

benign process!

Centrilobular (tree-in-bud)

• Tuberculosis and atypical mycobacterial

infection have rather discrete nodular

appearance, and are often differentiated

from other etiologies

Tuberculosis

Ground-Glass Opacity

• GGO implies long list of differential

diagnoses!

• Almost anything occupying either alveoli or

interstitium, or both!

Ground-Glass Opacity

• Alveolar proteinosis

• Acute chest syndrome

• Acute rejection of lung transplantation

• ARDS

• Acute interstitial pneumonia

• Acute radiation pneumonia

• Blood

• COP(BOOP)

• Bronchoalveolar lavage

• Brochiolitis (respiratory) associated ILD

• Bronchioalveolar cell carcinoma

Ground-Glass Opacity

• Cytomegalovirus and other pneumonias (PCP)

• Cancer and lymphoproliferative disorder

• Collagen vascular disease

• Contusion

• Drug toxicity

• Desquamative interstitial pneumonitis

• Extrinsic allergic alveolitis

• Eosinophillic pneumonia

• Edema

• Fibrois

• Granulomatous disease

Hypersensitivity Pneumonitis

• Faint diffuse ground-glass

opacity

• Centrilobular density

• Air trapping on

expiratory HRCT

Hypersensitivity Pneumonitis

• An allergic lung disease that results from

the inhalation of variety of organic dust

antigens

• Pathologically characterized by interstitial

mononuclear cell infiltrate, cellular

bronchiolitis and non-necrotizing

epithelioid granulomas

Hypersensitivity Pneumonitis

Ground-Class Opacity

• Hypersensitivity Pneumonitis

• Diffuse infection such as PCP

• Pulmonary edema

• Aspiration

• Hemorrhage

PCP and collagen vascular disease

COP (BOOP)

Alveolar Proteinosis

The First Question

Is this IPF/collagen vascular

disease/asbestosis/ (NSIP)?

IPF/collagen vascular disease/(asbestosis)

• Peripheral and basilar

• Honeycoming

• Decreased lung volume unless associated

with emphysema

Useful Patterns

• Nodular

• Linear (lymphatic system)

Non-Useful Patterns

• Reticular

• Recticulo-nodular

Nodular (fine)

• Miliary tuberculosis

• Metastasis

• Miliary sarcoidosis

Nodular (middle size or larger)

• Metastasis

• Metastasis

• Metastasis

Linear (lymphastic system)

• Pulmonary edema

• Sarcoidosis

• Lymphangitic spread of tumor

• Lymphoproliferative disorders

Centrilobular (tree-in-bud)

• Airway-related

• Most likely infection or inflammation

• I do not know what it is, however, it is

probably benign process!

Centrilobular (tree-in-bud)

• Tuberculosis and atypical mycobacterial

infection have rather discrete nodular

appearance, and are often differentiated

from other etiologies

Ground-Glass Opacity

• GGO implies long list of differential

diagnoses!

• Almost anything occupying either alveoli or

interstitium, or both!

Ground-Class Opacity

• Hypersensitivity Pneumonitis

• Diffuse infection such as PCP

• Pulmonary edema

• Aspiration

• Hemorrhage

Case 1

IPF/Collagen Vascular Disease

Case 2

Miliary Tuberculosis

Case 3

Metastasis

Lung Cancer

Case 4

Lymphangitic Spread of Tumor

Case 5

Pulmonary Sarcoidosis

Case 6

Hypersensitivity Pneumonitis

Advanced Problems

Categories Not Discussed for Simplification

• Emphysema

• Bronchiectasis

• Small airway disease

• Bilateral multifocal opacities

(infections, tumors, vasculitis,

BOOP/CEP)

Cautions!

• This is an approach to HRCT for diffuse

lung disease.

• May be too simplified.

• However, it may help to develop your own

approach.

Pulmonary edema

pulmonary hemorrhage

NSIP

IPF

Every child is an artist. The problem is

how to remain an artist once he grows up.

Bad artists copy.

Good artists steal.

Computers are useless, they can only give

you answers.

---Pablo Picasso

Reference

Nishino M, Itoh H, Hatabu H.

A practical approach to high-resolution CT of

diffuse lung disease. Eur J Radiol. 2013 Feb

11. [Epub]