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]
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