HRCT patterns in ILDs

2. Snap Shots on HRCT
Patterns in Interstitial
Lung Diseases
Gamal Rabie Agmy, MD, FCCP
Professor of chest Diseases,
Assiut university

3. The interstitium of the lung is not normally visible radiographic-
ally; it becomes visible only when disease (e.g., edema,
fibrosis, tumor) increases its volume and attenuation.
The interstitial space is defined as continuum of loose
connective tissue throughout the lung composed of three
subdivisions:
(i) the bronchovascular (axial), surrounding the bronchi,
arteries, and veins from the lung root to the level of the
respiratory bronchiole
(ii) the parenchymal (acinar), situated between the alveolar
and capillary basement membranes
(iii) the subpleural, situated beneath the pleura, as well as in
the interlobular septae.
The Lung Interstitium

4. Secondary pulmonary lobular
anatomy

5. The terminal bronchiole in the center
divides into respiratory bronchioles with
acini that contain alveoli.
Lymphatics and veins run within the
interlobular septa
Centrilobular area in blue (left)
and perilymphatic area in yellow
(right)

6. Ideal ILD doctor
Radiologist
Pathologist
Pulmonologist

7. Nodular Patternitie
By
Gamal Rabie Agmy , MD , FCCP
Professor of Chest Diseases ,Assiut University

8. Nodular Pattern

9. Nodular pattern
 A nodular pattern consists of multiple round opacities,
generally ranging in diameter from 1 mm to 1 cm
 Nodular opacities may be described as miliary (1 to 2 mm,
the size of millet seeds), small, medium, or large, as the
diameter of the opacities increases
 A nodular pattern, especially with predominant distribution,
suggests a specific differential diagnosis

10. Perilymphatic distribution
Centrilobular distribution
Random distribution

11. ARE NODULES IN CONTACT
WITH PLEURA
NO
CENTRILOBULAR
YES
PERILYMPHATIC RANDOM

14. TO SUM UP..
• Random
– touch pleura
– scattered in lung
• Centrilobular
–away from pleura
• Perilymphatic
– around vessels, bronchi
– touch pleura or fissure

16. Interstitial
nodules
Air space opacity
Miliary tuberculosis
sarcoidosis
in a lung transplant patient
with bronchopneumonia

17. Differential diagnosis of a nodular
pattern of interstitial lung disease
SHRIMP
Sarcoidosis
Histiocytosis (Langerhan cell
histiocytosis)
Hypersensitivity pneumonitis
Rheumatoid nodules
Infection (mycobacterial, fungal, viral)
Metastases, Miliary TB
Microlithiasis, alveolar
Pneumoconioses (silicosis, coal
worker's, berylliosis)

18. Cystic Lung Lesions
By
Gamal Rabie Agmy , MD , FCCP
Professor of Chest Diseases ,Assiut University

19. DECREASED LUNG
ATTENUATION

20. Lung Cysts
Pulmonary fibrosis (Honeycombing)
Lymphangiomyomatosis
Langerhanscell histiocytosis
Lymphocytic Interstitial Pneumonia (LIP)
Differential Diagnosis

21. Rough Reticular Fine Reticular
Traction
Bronchiectasis
and
Interface
sign
Honey
combing
UIP UIP or NSIP

22. Usual Interstitial Pneumonia UIP
HRCT Findings
Reticular opacities, thickened intra- and
interlobular septa
Irregular interfaces
Honey combing and parenchymal distorsion
Ground glass opacities (never prominent)
Basal and subpleural predominance

23. Basal and subpleural distribution
UIP

24. The Many ‘HRCT Faces’ of NSIP
Honeycombing not a
prominent feature !!!!

25. Lymphangioleiomyomatosis (LAM)
HRCT Morphology
Thin-walled cysts (2mm - 5cm)
Uniform in size / rarely confluent
Homogeneous distribution
Chylous pleural effusion
Lymphadenopathy
in young women

28. Lymphangioleiomyomatosis (LAM)

29. Tuberous Sclerosis (young man)

30. Langerhans Cell
Histiocytosis

31. Langerhans Cell Histiocytosis
HRCT Findings
Small peribronchiolar nodules (1-5mm)
Thin-walled cysts (< 1cm),
Bizarre and confluent
Ground glass opacities
Late signs: irreversible / parenchymal fibrosis
Honey comb lung, septal thickening, bronchiectasis

32. 1 year later
Peribronchiolar Nodules Cavitating nodules and cysts
Langerhans Cell Histiocytosis

33. Langerhans Cell Histiocytosis

34. Langerhans Cell Histiozytosis
Key Features
Upper lobe predominance
Combination of cysts and noduli
Characteristic stages
Increased Lung volume
Sparing of costophrenic angle
S
M
O
K
I
N
G

35. Langerhans Cell Histiocytosis

36. Langerhans Cell Histiocytosis
Differential Diagnosis
Only small nodules
Sarkoidosis, Silikosis
Only cysts
idiopathic Fibrosis
LAM
Destruktive emphysema

37. A professional diver.............

38. .......after cessation of smoking

39. Benign lymphoproliferative disorder
Diffuse interstitial infiltration of
mononuclear cells
Not limited to the air ways as
in follicular Bronchiolitis
LIP
= Lymphocytic Interstitial Pneumonia

40. Sjögren: LIP

41. LIP
= Lymphocytic Interstitial Pneumonia
Rarely idiopathic
In association with:
Sjögren’s syndrome
Immune deficiency syndromes, AIDS
Primary biliary cirrhosis
Multicentric Castlemean’s disease

42. Sjoegren disease
Dry eye and dry mouth
Fibrosis, bronchitis and bronchiolitis
LIP
Overlap
Sarcoid, DM/PM, MXCT
SLE, RA (pleural effusion)
Up to 40 x increased risk for lymphoma (mediastinal
adenopathy) and
2 x times increased risk for neoplasma

43. Mosiac pattern

44. Where is the pathology ???????
in the areas with increased density
meaning there is ground glass
in the areas with decreased density
meaning there is air trapping

45. Pathology in black areas
Airtrapping: Airway
Disease
Bronchiolitis obliterans (constrictive bronchiolitis)
idiopathic, connective tissue diseases, drug reaction,
after transplantation, after infection
Hypersensitivity pneumonitis
granulomatous inflammation of bronchiolar wall
Sarcoidosis
granulomatous inflammation of bronchiolar wall
Asthma / Bronchiectasis / Airway diseases

46. Airway Disease
what you see……
In inspiration
sharply demarcated areas of seemingly increased
density (normal) and decreased density
demarcation by interlobular septa
In expiration
‘black’ areas remain in volume and density
‘white’ areas decrease in volume and increase in
density
INCREASE IN CONTRAST
DIFFERENCES
AIRTRAPPING

47. Bronchiolitis
obliterans

48. Early Sarcoidosis

49. Chronic
EAA

50. Hypersensitivity pneumonitis
Extr. Allerg. Alveolitis (EAA)HRCT
Morphology
chronic: fibrosis
Intra- / interlobular septal thickening
Irregular interfaces
Traction bronchiectasis
acute - subacute
acinar (centrilobular) unsharp densities
ground glass (patchy - diffuse)

53. Pathology in white Areas
Alveolitis / Pneumonitis
Ground glass
desquamative intertitial pneumoinia (DIP)
nonspecific interstitial pneumonia (NSIP)
organizing pneumonia
In expiration
both areas (white and black) decrease in
volume and increase in density
DECREASE IN CONTRAST
DIFFERENCES

54. DI
P

55. Cellular
NSIP

56. Mosaic Perfusion
Chronic pulmonary embolism
LOOK FOR
Pulmonary hypertension
idiopathic, cardiac disease, pulmonary
disease

57. CTEPH =
Chronic thrombembolic
pulmonary hypertension

58. Reticular Pattern
Gamal Rabie Agmy, MD, FCCP
Professor of chest Diseases,
Assiut university

59. Reticular Pattern
A reticular pattern results from the summation
or superimposition of irregular linear opacities.
The term reticular is defined as meshed, or in
the form of a network. Reticular opacities can be
described as fine, medium, or coarse, as the
width of the opacities increases.
A classic reticular pattern is seen with
pulmonary fibrosis, in which multiple curvilinear
opacities form small cystic spaces along the
pleural margins and lung bases (honeycomb
lung)

60. HRCT of the lung
Reticular pattern – definition
Glossary of Terms for Thoracic Imaging – Radiology 2008; 246:697

61. HRCT of the lung
 thickening of the interstitial fiber network by
Reticular pattern – significance
 fluid
 fibrous tissue
 infiltration by cells or other material
 pulm. edema
 lymphangitic carcin.
 veno-occlusive dis.
 alveolar proteinosis
 IPF
 collagen vascular dis.
 drug-related fibrosis
 amyloidosis
Predominant pattern Associated / occasional
finding
 sarcoidosis
 pneumoconiosis
 pulm. hemorrhage
 asbestosis

62. HRCT of the lung
Reticular pattern – HRCT
numerous, clearly visible interlobular septa
outlining lobules of characteristic size and shape
interlobular septal thickening
very fine network of lines within visible lobules
intralobular interstitial thickening
several layers of air-filled cysts, 3-10 mm in diameter,
with thick walls (1-3 mm)
honeycombing

63. Reticular pattern
Interlobular septal thickening – dd
smooth
thickening
pulm. edema
pulm. hemorrhage
lymphangitic carc.
lymphoma
nodular
thickening
lymphangitic carc.
sarcoidosis
amyloidosis
irregular
thickening
fibrosis

64. Reticular pattern
Interlobular septal thickening – pulmonary edema
 smooth septal thickening, isolated or in combination
with ground-glass opacity
 peribronchovascular and subpleural interstitial th.
 perihilar and gravitational distribution, bilateral
 findings of CHF

65. Reticular pattern
Interlobular septal th. – lymphangitic carcinomatosis
 tumor filling of pulmonary vessels and lymphatics
 direct tumor infiltration of the interstitium
 vascular and lymphatic distension distally to tumor
emboli or obstruction
 breast ca.
 lung ca.
 stomach ca.
 pancreas ca.
Secondary to:
 prostate ca.
 adenoca. of
unknown origin

66. Reticular pattern
Interlobular septal th. – lymphangitic carcinomatosis
 smooth or nodular septal thickening
 smooth or nodular thickening of peribronchovascular
interstitium and fissures
 thickening of the intralobular axial interstitium
 focal or asymmetric distribution

67. Reticular pattern
Interlobular septal thickening – sarcoidosis
 reticulation is not a predominat finding
 distorsion of the lung architecture and secondary
lobule anatomy is common, especially when septal
thickening is present
 upper lobe predominance

68. Reticulation or not reticulation ……
“crazy paving”

69. Reticulation or not reticulation ……
alveolar proteinosis

70. Reticular pattern
Interlobular septal thickening – “crazy paving”
 scattered or diffuse ground-glass attenuation with
superimposed interlobular septal thickening and
intralobular lines
 described in a variety of infectious, neoplastic,
idiopathic, inhalation, and sanguineous disorders of
the lung
Rossi SE – Radiographics 2003; 23:1509

71. Reticular pattern
Honeycombing – significance
air-containing cystic spaces having thick,
fibrous walls lined by bronchiolar
epithelium

fibrosis is present
UIP is likely the histologic pattern
IPF is very likely, in the absence of a
known disease

72. Reticular pattern
Honeycombing – differential diagnosis
basal
distribution
middle/upper
distribution
chronic HP
sarcoidosis
IPF
collagen vasc. dis.
asbestosis
drugs

73.  honeycombing /
intralobular reticulation
 basal and peripheral
distribution
typical HRCT findings
sens. 77%
spec. 72%
PPV 85%
PPV 96%*
Swigris JJ – Chest 2005; 127:275
lung biopsy in patients who
do not show typical features
Reticular pattern
Honeycombing – idiopathic pulmonary fibrosis
* confident diagnosis

74. Reticular pattern
Honeycombing – collagen vascular diseases
 rheumatoid arthritis and scleroderma
 almost indistinguishable from UIP due to IPF
 associated findings, typical of the disease, may help in the
differential diagnosis

75. Reticular pattern
Honeycombing – drug reaction
 findings of fibrosis, similar to those seen in IPF
 peripheral and subpleural predominance
 highest incidence with cytotoxic agents
 temporal relationship between drug administration and
development of pulmonary abnormalities
Honeycombing – chronic hypersensitivity pneum.
 possible association with poorly
defined nodules, mosaic attenuation
or air-trapping
 upper and middle zone
predominance

76. Reticular pattern
Intralobular interstitial thickening – significance
thickening of the pulmonary interstitium
at a sublobular level
isolated (fibrosis)
in association with septal thickening
or the “crazy paving” pattern
very fine linear structures below the
resolution of HRCT (gg appearance)


77. Reticular pattern
adapted from: Webb RW – HRCT of the lung, III ed; 2001
interlobular septal thickening
irregular, lung
distorsion
nodular
smooth
•fibrosis
(sarcoidosis,
asbestosis)
•pulm. edema
•linf. carc.
•hemorrhage
•sarcoidosis
•linf. carc.

78. Reticular pattern
adapted from: Webb RW – HRCT of the lung, III ed; 2001
honeycombing
•IPF (60%)
•collagen vascular dis.
•drug reaction
•asbestosis (uncommon)
subpleural, posterior
LL predominance
•sarcoidosis
•chronic HP
•radiation
other distribution
(UL; parahilar)

79. Reticular pattern
adapted from: Webb RW – HRCT of the lung, III ed; 2001
intralobular interstitial thickening
& septal thickening & GGO
isolated
NSIP
findings of fibrosis
honeycombing
differential dx

80. Tree-in-bud
 Centrilobular nodules m/b further characterized by presence or
absence of ‘‘tree-in-bud.’’
 Tree-in-bud -- Impaction of centrilobular bronchus with mucous,
pus, or fluid, resulting in dilation of the bronchus, with associated
peribronchiolar inflammation .
 Dilated, impacted bronchi produce Y- or V-shaped structures
 This finding is almost always seen with pulmonary infections.
80

81. Tree-in-bud
Tree-in-bud describes the appearance of an irregular and often nodular
branching structure, most easily identified in the lung periphery.

82. Head cheese sign
It refers to mixed
densities which includes
# consolidation
# ground glass
opacities
# normal lung
# Mosaic perfusion
• Signifies mixed
infiltrative and
obstructive disease

83. Head cheese sign
Common cause are :
1. Hypersensitive pneumonitis
2. Sarcoidosis
3. DIP
83

84. How To Approach
a Practical
Diagnosis?

85. An acute appearance suggests pulmonary
edema, acute milliary TB, or pneumonia
Rule no. 1

86. Disseminated histoplasmosis and reticulonodular ILD.
A: PA chest radiograph, close-up of right upper lung, shows reticulonodular
ILD.
B: CT scan shows multiple circumscribed round pulmonary nodules, 2 to 3
mm in diameter.

87. Reticulonodular lower lung predominant
distribution with decreased lung volumes
suggests: (APC)
1. Asbestosis
2. Aspiration (chronic)
3. Pulmonary fibrosis (idiopathic)
4.Collagen vascular disease
Rule no. 2

88. Asbestos-related
pleural disease and
asbestosis

89. Pulmonary fibrosis and rheumatoid arthritis.

90. Systemic sclerosis.
A: PA chest radiograph shows a bibasilar and subpleural distribution of fine
reticular ILD. The presence of a dilated esophagus (arrows) provides a clue
to the correct diagnosis.
B: CT scan shows peripheral ILD and a dilated esophagus (arrow).

91. A middle or upper lung predominant distribution
suggests: (Mycobacterium Settle Superiorly in
Lung)
1. Mycobacterial or fungal disease
2. Silicosis
3. Sarcoidosis
4. Langerhans Cell Histiocytosis
Rule no. 3

92. Complicated silicosis. PA chest radiograph shows multiple
nodules involving the upper and middle lungs, with coalescence
of nodules in the left upper lobe resulting in early progressive
massive fibrosis

93. Sarcoidosis. CT scan shows nodular thickening of the bronchovascular
bundles (solid arrow) and subpleural nodules (dashed arrow), illustrating the
typical perilymphatic distribution of sarcoidosis.

94. Langerhan cell histiocytosis.
This 50-year-old man had a
30 pack-year history of
cigarette smoking.
A: PA chest radiograph
shows hyperinflation of the
lungs and fine bilateral
reticular ILD.
B: CT scan shows multiple
cysts (solid arrow) and
nodules (dashed arrow).

95. Associated lymphadenopathy suggests :
1.Sarcoidosis
2.neoplasm (lymphangitic carcinomatosis,
lymphoma, metastases)
3. infection (viral, mycobacterial, or fungal)
4. silicosis
Rule no. 4

96. Simple silicosis.
A: CT scan with lung windowing shows numerous
circumscribed pulmonary nodules, 2 to 3 mm in diameter
(arrows).
B: CT scan with mediastinal windowing shows densely
calcified hilar (solid arrows) and subcarinal (dashed arrow)
nodes.

97. Associated pleural thickening and/or
calcification suggest asbestosis.
Rule no. 5

98. Associated pleural effusion suggests :
1.pulmonary edema
2.lymphangitic carcinomatosis
3.lymphoma
4.collagen vascular disease
Rule no. 6

99. Cardiogenic pulmonary edema.
PA chest radiograph shows enlargement of the cardiac
silhouette, bilateral ILD, enlargement of the azygos vein
(solid arrow), and peribronchial cuffing (dashed arrow).

100. Lymphangitic carcinomatosis. This 53-year-old man
presented with chronic obstructive pulmonary disease and
large-cell bronchogenic carcinoma of the right lung.
CT scan shows unilateral nodular thickening (arrows) and a
malignant right pleural effusion.

101. Associated pneumothorax suggests
lymphangioleiomyomatosis or LCH.
Rule no. 7

102. Lymphangioleiomyomatosis
(LAM).
A: PA chest radiograph shows a
right basilar pneumothorax and
two right pleural drainage
catheters. The lung volumes are
increased, which is
characteristic of LAM, and there
is diffuse reticular ILD.
B: CT scan shows bilateral thin-
walled cysts and a loculated
right pneumothorax (P).