This document discusses idiopathic interstitial pneumonias (IIPs), a group of diffuse lung diseases of unknown cause associated with interstitial lung inflammation and fibrosis. It defines two main types of IIPs - idiopathic pulmonary fibrosis (IPF), characterized by usual interstitial pneumonia (UIP) pattern on imaging and histology, and nonspecific interstitial pneumonia (NSIP). IPF typically appears on CT as subpleural reticulation with honeycombing and traction bronchiectasis, worse in the lung bases. NSIP usually shows more symmetric ground-glass opacity, reticulation and micronodules without honeycombing. Differential diagnosis relies on distinguishing imaging patterns between

1. ILD

2. CONTENTS
• DEFINITION
• CLASSIFICATION
• APPROACH TO ILDS
• IMAGING FINDINGS
• DIAGNOSIS

3. NORMAL ANATOMY : THE SECONDARY
PULMONARY LOBULE AND ACINUS
• The secondary lobule is the basic
anatomic unit of pulmonary
structure and function
• Pulmonary lobule ranges from 1
to 2.5 cm in size
• Central portion of the secondary
lobule reffered to as centrilobular
region contains the pulmonary
artery and centrilobular
bronchiole normally is invisible

4. • Each pulmonary lobule is
marginated by connective tissue
interlobular septa which contains
the pulmonary veins and
lymphatics
• Acinus is the largest unit of lung
structure which partcipate in gas
exchange
• A pulmonary lobule usually consist
of a dozen or fewer acini, acini are
not visible on HRCT

6. DEFINITION
• Heterogeneous group of diffuse lung diseases occuring
without known cause and associated with varying degrees of
interstitial lung inflammation and fibrosis

7. IDIOPATHIC INTERSTITIAL PNEUMONIAS
(IIPS)
• Include 7 entities:
• Idiopathic pulmonary fibrosis - characterized by the morphologic pattern of usual
interstitial pneumonia (UIP)
• Nonspecific interstitial pneumonia (NSIP)
• Cryptogenic organizing pneumonia (COP)
• Respiratory bronchiolitis–associated interstitial lung disease (RB-ILD)
• Desquamative interstitial pneumonia (DIP)
• Lymphoid interstitial pneumonia (LIP)
• Acute interstitial pneumonia (AIP)

10. A HRCT APPROACH TO THE DIAGNOSIS
OF THE INTERSTITIAL PNEUMONIA$:
1. Honeycombing with a basal and subpleural predominance in the absence of a known disease or exposure,
is highly suggestive of UIP IIPF. Lung biopsy is uncommonly performed when HRCT shows these
findings.
2. Concentric lower lobe ground-glass opacity without honeycombing suggests NSIP. In a patient with
collagen vascular disease, biopsy is uncommonly performed.
3. Subpleural sparing of abnormalities (reticulation or ground-glass opacity) strongly suggests NSlP.
4. Patchy or nodular subpleural or peribronchial consolidation is typical of COP. The atoll or reversed halo
sign suggests this diagnosis.
5. ARDS with typical plain film or CT findings, without known cause, may be AIP.
6. Diffuse or centrilobular ground-glass opacity in a smoker is typical of DIP or RB-lLD.
7. Cystic air spaces or ground-glass opacity may represent LIP. LIP is usually associated with other
diseases.

11. CLASSIFICATION
• These disorders were categorized according to different clinical, radiologic, and
histologic classifications
• 2001, the American Thoracic Society (ATS) and European Respiratory Society
(ERS)standardized the terminology for IIPs (Fig 1) (3).
• This new ATS-ERS classification is the result of a multidisciplinary consensus and
includes seven disease entities:

12. • Terminology for the IIPs with the various subentities according to the
ATS-ERS classification. UIP - usual interstitial pneumonia.

14. IDIOPATHIC PULMONARY FIBROSIS
• Most common
• By definition, associated with the morphologic pattern of UIP
• survival -2 to 4 years,
• poorer prognosis than NSIP, COP, RB-ILD, DIP, and LIP

15. CHEST RADIOGRAPH
• 80% - bilateral reticular pattern predominantly involving the lower lung zones
and subpleural lung regions
• earliest stages- a fine reticular pattern may be visible in the posterior
costophrenic angles on the lateral radiograph
• In advanced disease, shows decreased lung volumes and subpleural reticular
opacities that increase from the apex to the bases of the lungs

16. • Chest radiograph and HRcr in a patient with histologically proven idiopathic pulmonary fibrosis. A: PA radiograph
shows reduced lung volumes. There is an increase in reticularopacities in the lung periphery and at the lung bases.
The appearance and distribution are typical of idiopathic pulmonary fibrosis. B: Detail view of the right lower lobe
shows increased reticular opacities.

17. • Lateral view shows increased reticular opacities in the
posterior costophrenic angles
• (blade arrow). A major fissure (white orrows) is
bowed posteriorly because of more severe fibrosis
• in the lower lobe

18. CT
• earliest stages, the only HRCT abnormality may be fine reticulation in the subpleural lung

19. TRIO OF SIGNS SUGGESTIVE OF UIP :
• Subpleural reticular opacities
• macrocystic honeycombing combined with traction bronchiectasis
• Apicobasal gradient
• Typical patient with UIP- disease is most extensive on the most basal
section

20. • Distribution (a), CT image (b), and CT pattern (c) of UIP. The distribution is subpleural with an
apicobasal gradient (red area in a). CT shows honeycombing (green areas in c), reticular opacities
(blue areas in c), traction bronchiectasis (red area in c), and focal ground-glass opacity (gray area in
c).

21. • (4) IPF in a 64-year-old man. (a) High-resolution CT image obtained at presentation shows reticular
opacities, honeycombing (arrowhead), and focal ground-glass opacity (thick arrow). Moderate traction
bronchiecta sis is present (thin arrow). These findings are consistent with the UIP pattern. (b) Follow-up CT
image obtained 12 months later shows marked progression of the honeycombing (arrowheads) and traction
bronchiectasis (arrows).

22. • Prone HRCT shows extensive
subpleural reticular opacities
with mild honeycombing.
• The major fissures (arrows) are
displaced posteriorly because of
lower lobe fibrosis.

23. • Acute exacerbation of idiopathic pulmonary fibrosis. Supine (A) and prone (B) HROs show
subpleural reticulation and honeycombing in tfte lower lobes, typical of idiopathic pulmonary
fibrosis. Supine (C) and prone (D) HRCTs at the time of an acute exacerbation show progression
of honeycombing and an increase in ground-glass opacity.this reflects diffuse alveolar damage.

24. DIAGNOSTIC CRITERIA FOR IDIOPATHIC
PULMONARY FIBROSIS:
A FLEISCHNER SOCIETY WHITE PAPER

26. e
TYPICAL UIP PATTERN
Fleishner Society

27. Probable UIP pattern
ATS/ERS/ JRS/ALAT
Fleishner Society

28. CT pattern indeterminate for UIP
UIP was proven at biopsy
Indeterminate for UIP

29. Alternate diagnosis
Fibrotic Hypersensitiveity
pneumonitis
Consistent with non IPF diagnosis
Fibrotic Hypersensitiveity pneumonitis
Non IPF/ Alternative diagnosis

30. NONSPECIFIC INTERSTITIAL PNEUMONIA
• less common than UIP
• associated with a variety of imaging and histologic findings, and the
diagnostic approach is highly challenging.

31. • primarily defined as an idiopathic disease
• Morphologic pattern of NSIP- in association with frequent disorders,
such as connective tissue diseases, hypersensitivity pneumonitis, or
drug exposure – SECONDARY FORM

32. CHEST RADIOGRAPH
• ill-defined opacity, ground-glass opacity, or consolidation
predominantly involving the lower lung zones
• Other manifestations include a reticular pattern or a combination of
reticular and air-space patterns.
• 10% or more of cases. the chest radiograph is normal.
• The lower lung lobes are more frequently involved,
• but an obvious apicobasal gradient, as seen in UIP, is usually missing

33. • Nonspecific interstitial pneumonia.
A: Chest radiograph shows a subde
increase in opacity at the lung
bases.

34. • Nonspecific interstitial
pneumonia. A: Chest
• radiograph shows a subtle
increase in ground-glass opacity
• at the lung bases.

35. CT
• Typically - a sub pleural and rather symmetric distribution of lung abnormalities
• Most common - patchy ground-glass opacities combined with irregular linear or
reticular opacities and scattered micronodules and traction bronchiectasis

36. • Distribution (a), CT image (b), and CT pattern (c) of NSIP. The distribution is
subpleural with no obvious gradient (red area in a). CT shows ground-glass opacity
(gray areas in c), irregular linear and reticular opacities (blue areas in c),
micronodules (red areas in c), and microcystic honeycombing (green areas in c).

37. • In advanced disease, traction bronchiectasis and consolidation can be seen;
• ground-glass opacities remain the most obvious high-resolution CT feature in the
typical patient with NSIP

38. • NSIP in a 60-year-old woman with mild dyspnea and fatigue. (a) High-resolution CT
image of the lower lungs shows bilateral subpleural ground-glass opacities (arrowhead)
and irregular linear opacities (arrow). The patient received corticosteroid treatment. (b)
Follow-up CT image obtained 6 months later shows improvement, with partial resolution
of the ground-glass opacities (arrowhead) and linear opacities (arrow).

39. • NSIP should be strongly considered if HRCT shows ground-glass opacity or reticulation, without
honeycombing, in the subpleural and basal lung, particularly if subpleural sparing is present.
• NSIP may show sparing of the immediate subpleural region- differentiates from UIP

40. • Nonspecific interstitial pneumonia with ground-glass opacity. Supine HRCTs show ground-glass opacity
with superimposed fine reticulation. Abnormalities predominate at the lung bases. 11tere is sparing of the
immediate subpleural lung. Biopsy showed ceJiular nonspecific interstitial pneumonia.

41. • Other findings in advanced - subpleural cysts, but compared to those of UIP, these cysts are
smaller and limited in extent
• The term “microcystic honeycombing” is used for these cystic changes in NSIP, as opposed to
the macrocystic honeycombing seen in UIP
• cellular and fibrotic NSIP – similar findings – but honeycombing -exclusively in patients
with fibrotic NSIP
• Other findings- increased likelihood of fibrosis in NSIP - extent of traction bronchiectasis
and intralobular reticular opacities

42. • NSIP in a 53-year-old man with mild dyspnea. (a) Coronal CT image shows diffuse lung
involvement consisting of peripherally located irregular linear opacities with ground-
glass opacities (arrows). Small cystic lesions are seen (arrowhead). (b) Axial high-
resolution CT image shows the small cystic lesions more clearly (arrowhead).

43. DIFFERENCE BETWEEN UIP & NSIP
• CT features favor the diagnosis of NSIP over UIP are :
• homogeneous lung involvement without an obvious apicobasal gradient, extensive
ground-glass abnormalities, a finer reticular pattern, and micronodules
• Follow up CT differences :
• NSIP- ground-glass opacities usually do not progress to areas of honeycombing, even if
there is associated bronchiectasis
• UIP- progression of ground-glass attenuation to honeycombing is common and indicates
irreversible fibrosis

44. • Comparison of high-
resolution CT features
between UIP and NSIP.
• (a) UIP is characterized by
heterogeneous lung
abnormalities consisting of
subpleural honeycombing
(arrowhead), reticular
opacities, and traction
bronchiectasis. (b) NSIP
demonstrates homogeneous
lung involvement with
predominance of ground-
glass opacity combined with
subpleural linear opacities
and micronodules. The
microcysts in NSIP
(arrowhead) are much
smaller than the
honeycombing in UIP.

45. • Key imaging
features for
differentiation
between UIP and
NSIP.

46. Hypersensitivity
pneumonitis

47. Non fibrotic Hypersensitivity pneumonitis

48. Non fibrotic Hypersensitivity pneumonitis

51. Fibrotic Hypersensitivity pneumonitis

52. Fibrotic Hypersensitivity
pneumonitis
• Chronic
• Upper lobe predominant
• Honeycombing

53. Three density sign or Head Cheese
sign
Hypersensitivity pneumonitis

54. CTD related ILD

55. CTD RELATED ILD
• Systemic Lupus Erythematosus Nonspecific interstitial pneumonia(NSIP)
• Rheumatoid Arthritis Usual interstitial pneumonia (UIP)
• Progressive systemic sclerosis Organizing pneumonia (OP)
• Dermatomyositis Diffuse alveolar damage (DAD)
• Polymyositis Lymphoid interstitial pneumonia (LIP)
• Ankylosing spondylitis
• Sjogren’s syndrome

56. Straight Edge sign - fairly
straight and abrupt
interphase between fibrotic
lung bases and normal lung
without extension along the
lateral
margins of lung on coronal
images
CTD related UIP

57. The AUL sign is concentration of
fibrosis in anterior aspect of
upper lobes with relative sparing
of rest of the upper lobes along
with concomitant lower lobe
involvement
CTD related UIP

58. Exuberant honey combing sign (EHC
sign) is extensive honeycomb like cyst
formation in greater than 70 % of fibrotic
portion of lungs
CTD related UIP

60. CRYPTOGENIC ORGANIZING PNEUMONIA
• Organizing pneumonia ( OP) - histologic pattern characterized by the presence of patchy areas of organizing
pneumonia, consisting largely of mononuclear cells, foamy macrophages, and organizing fibrosis in
peripheral air spaces, including bronchioles, alveolar ducts, and alveoli
• is also known as bronchiolitis obliterans organizing pneumonia (BOOP),

61. • typical patient - 55 years.
• M=F
• mild dyspnea, cough, and fever that have been developing over a few weeks
• no association with cigarette smoking; in fact, most patients are nonsmokers or ex-
smokers

62. • Typically, there is patchy lung involvement with preservation of lung architecture

63. CHEST RADIOGRAPH
• usually shows unilateral or bilateral patchy consolidations that resemble pneumonic
infiltrates
• consolidations in COP do not represent an active pneumonia but result from
intraalveolar fibroblast proliferations- associated with prior respiratory infection.
• Some - Small nodular opacities or larger nodules
• Lung volumes are preserved in most patients.
• In some -consolidation is peripheral, a pattern similar to that seen in chronic eosinophilic pneumonia.

64. • Focal consolidation in cryptogenic
organizing pneumonia/bronchiolitis
obliterans organizing pneumonia. A: Chest
radiograph shows focal consolidation in the
right lower lobe (a"ow).

65. CT
• involves the lower lung zones to a greater degree than the upper lung zones.
• patchy peripheral or peribronchial consolidation is common,
cryptogenic organizing pneumonia/bronchiolitis obliterans organizing pneumonia (COP/BOOP). n.e classic appearance of
COP/BOOP is patchy subpleural and peribronchialconsolidation. In this patient, subpleural consolidation predominates

66. • Distribution (a), CT image (b), and CT pattern (c) of COP. The distribution is peripheral or
peribronchial with a basal predominance (red areas in a). CT shows consolidation with air
bronchograms (dark gray areas in c), ground-glass opacities (light gray areas in c), linear
opacities (blue areas in c), and mild bronchial dilatation (red areas in c).

67. CT
• Patchy consolidation (80% of cases) or ground-glass opacity (60%), often with a subpleural and/or
peribronchial distribution
• 2. Small, ill-defined nodules (30% to 50% of cases) which may be peribronchial or peribronchiolar (i.e.,
centrilobular;
• 3. Large nodules or masses, which may be irregular in shape
• 4. Focal or lobar consolidation
• 5. The "atoll sign" or "reversed halo sign," in which ringshaped or crescentic opacities are seen, with
ground-glass opacity in the center of the ring (thus resembling a coral atoll or the reverse of the halo sign

68. • Subpleural and peribronchial consolidation in
ayptogenic organizing
pneumonia/bronchiolitis obliterans organizing
pneumonia. HRcr shows irregular nodular
areas of consolidation, many occurring in
relation to bronchi. Air bronchograms are
visible within the opacities. An example of the
•atoll'" or .,reversed halo" sign is visible in the
mid lung (arrow). n.e opacities have irregular
margins.

69. • Typical appearance - varies from ground glass to consolidation
• In consolidation- air bronchograms and mild cylindrical bronchial dilatation
common
• These opacities have a tendency to migrate, changing location and size, even
without treatment
• They are of variable size, ranging from a few centimeters to an entire lobe

70. • COP in a 54-year-old woman. (a) Coronal CT image shows extensive bilateral
peribronchial consolidation and ground-glass opacities (arrows). An endotracheal tube is
present (arrowhead), indicating the need for mechanical ventilation. (b) CT image
obtained after 3 weeks of corticosteroid and supportive treatment shows subtotal
resolution of the lung abnormalities (arrows).

71. • COP in a 69-year-old man. High-resolution CT image shows peripherally located
consolidation with air bronchograms and sparing of the subpleural space (arrow).

72. • atypical imaging findings include irregular linear opacities, solitary focal lesions
that resemble lung cancer, or multiple nodules that may cavitate

73. • Atypical appearances of COP. (a) CT image shows bizarrely shaped nodules, some of
which are cavitating (arrow). (b) CT image shows perilobular opacities that resemble
thickened interlobular septa (arrow).

74. • confirmed with surgical lung biopsy.

75. • majority of patients recover completely after administration of corticosteroids, but
relapses occur frequently within 3 months after corticosteroid therapy is reduced or
stopped

76. RESPIRATORY BRONCHIOLITIS–
ASSOCIATED INTERSTITIAL LUNG DISEASE
• smoking-related ILD
• usually 30 – 40 years
• smoking history of 30 pack-years
• Men -twice than women
• mild dyspnea and cough.

77. CHEST RADIOGRAPH
• insensitive for detection
• normal or can show nonspecific
bilateral. ill-defined opacities, usually
with a lower zonal predominance.
• Sometimes, bronchial wall
thickening or reticular opacities
can be seen

78. CT
• Not all patients with RB-ILD show abnormalities on HRCT.
• distribution is mostly diffuse
• The key features - centrilobular nodules in combination with ground-glass opacities and
bronchial wall thickening
• The ground-glass opacities have been shown to correlate with macrophage accumulation
in alveolar ducts and alveolar spaces
• centrilobular nodules – due to peribronchial distribution of the intraluminal infiltrates
• Coexisting moderate centrilobular emphysema is common

79. • Distribution (a), CT image (b), and CT pattern (c) of RB-ILD. RB-ILD has an upper lung predominance
(red area in a). CT shows ground-glass opacity (gray area in c) and centrilobular nodules (red areas in c)

80. • Biopsy proven
respiratory
bronchiolitisinter
stitial lung
disease. HRCT
shows patchy
areas of ground-
glass opacity.
Many of the
opacities are
• centrilobuJar.

81. • RB-ILD in a 44-year-old woman with a 20 pack-year smoking history. High-resolution CT
image of the upper lung lobes shows centrilobular nodules (white arrows) and patchy ground-
glass opacities (black arrow). Mild coexisting centrilobular emphysema is seen (arrowhead).

82. • Unlike patients with DIP. an upper lobe predominance is typical ofRB-ILD.
• A small percentage of patients (25%) show some reticular opacities due to fibrosis.

83. • Smoking cessation is the most important component in the therapeutic management
of RB-ILD. However, the majority of patients also receive corticosteroid therapy

84. DESQUAMATIVE
INTERSTITIAL PNEUMONIA
• strongly associated with cigarette smoking and is considered to represent the end of
a spectrum of RB-ILD
• also occurs in nonsmokers and has been related to a variety of conditions, including
lung infections and exposure to organic dust

85. • majority – btw 30 and 40 years
• Men - twice as often as women,
• most patients are current or past smokers (average smoking history of 18 pack-
years)

86. CHEST RADIOGRAPHS
• ground-glass opacities seen in the lower lung zones
• 25%- normal.
•
reduced lung volume and hazy ground-glass opacity
in the peripheral lung

87. CT
• characterized by diffuse ground-glass opacities,- due to homogeneous intraalveolar
accumulation of macrophages and thickening of alveolar septa
• Usually- peripheral and lower lung lobe predominance
• Other findings - irregular linear opacities and small cystic spaces, which are
indicative of fibrotic changes
• RB-ILD and DIP, imaging findings may overlap and may be indistinguishable from
each other.
• honeycombing or obvious fibrosis is rare.
• Because of its association with smoking, centrilobular emphysema may be visible.
• Small cystic lucencies, not representing emphysema, may also be seen in patients with DIP

88. • Distribution (a), CT image (b), and CT pattern (c) of DIP. DIP has a peripheral
predominance (red areas in a). CT shows ground-glass opacity (gray area in c),
irregular linear opacities (blue areas in c), and cysts (green areas in c).

89. • ground-glass opacity in the
peripheral lung.

90. • (22) DIP in a 55-year-old man. High-resolution CT image of the lower lung lobes shows extensive
bilateral ground-glass opacities (arrowhead). Coexisting moderate bronchial wall thickening is present
(arrow).
• (23) DIP in a 43-year-old man with a history of smoking. High-resolution CT image of the lower lung
zones shows patchy ground-glass opacities in both lungs, predominantly in the subpleural region

91. • With smoking cessation and corticosteroid therapy, the prognosis is good.
Nevertheless, progressive disease with eventual death can occur, notably in patients
with continued cigarette smoking

92. LYMPHOID INTERSTITIAL PNEUMONIA
• more common as a secondary disease in association with systemic disorders, Sjogren
syndrome, human immunodeficiency virus infection, and variable immunodeficiency
syndromes
• W>M
• fifth decade
• slowly progressive dyspnea and cough over a period of 3 or more years
• In the past, LIP was considered a pulmonary lymphoproliferative disorder, with
subsequent progression to malignant lymphoma
• Alveolar walls are extensively involved.

93. CHEST RADIOGRAPH
• Nonspecific: such as bilateral reticular, reticulonodular, or alveolar opacities.
• lower lung zones.
• Less common- a nodular pattern or air-space consolidation.

94. CT
• shows bilateral abnormalities that are diffuse or have a lower lung predominance.
• The dominant finding - ground-glass attenuation, which is related to the histologic
evidence of diffuse interstitial inflammation
• Another finding - thin-walled perivascular cysts
• cysts - within the lung parenchyma throughout the mid lung zones and presumably
result from air trapping due to peribronchiolar cellular infiltration (subpleural,
lower lung cystic changes in UIP)
• In combination with groundglass opacities, these cysts are highly suggestive of LIP.

95. • Poorly defined centrilobular nodules- correlates with the presence of lymphocytic infiltration predominantly
involving bronchioles (follicular bronchiolitis)
• most frequent in collagen-vascular disease or AIDS.
• 3. Small, well-defined nodules with a perilymphatic distribution or septal thickening mimicking
lymphangitic spread of carcinoma - due to interstitial in1iltration

96. • Distribution (a), CT image (b), and CT pattern (c) of LIP. The distribution is diffuse (red area
in a).CT shows ground-glass opacity (gray area in c) and perivascular cysts (green areas in c).

97. • LIP in a 47-year-old woman. (a) High-resolution CT image shows diffuse ground-glass opacity
(arrow) with multiple perivascular cysts (arrowheads) and reticular abnormalities ( * ). (b) CT
image obtained after corticosteroid therapy shows improvement, with partial resolution of the
ground-glass and reticular opacities and better demarcation of the perivascular cysts (arrowheads).

98. • Biopsy-proven lymphoid interstitial
pneumonia in a patient with common
variable immunodeficiency.
• HRCT shOtNS patchy areas of ground-
glass opacity. Some of the opacities
appear centrilobular

99. • Lung cysts in two patients with Sj6gren's syndrome and lymphoid interstitial pneumonia.
• A: Several isolated lung cysts are visible (arrows). B: Detail view of the right lung. Multiple scattered thin-
walled cysts are present. This appearance is typical of LIP in Sjogren's syndrome. n.e cysts are usually
limited in number.

100. • . Corticosteroids are used in the therapy of LIP, but response is unpredictable and no
controlled randomized treatment trials have been reported to date

101. ACUTE INTERSTITIAL PNEUMONIA
• fulminant disease of unknown cause, usually occurring in a previously healthy person.
• associated with diffuse alveolar damage (DAD) with alveolar hyaline membranes and ~ active
interstitial :fibrosis
• only entity among the IIPs with acute onset of symptom
• 50 years
• severe dyspnea with a need for mechanical ventilation within less than 3 weeks
• Typically, a history of viral-like illness exists.
• M =F ,
• cigarette smoking not a risk for development of AIP.

102. XRAY , CT
• bilateral air-space consolidation or ground-glass opacity that is diffuse (50%) or may predominate in the upper
(25%) or lower (25%) lung zones
• more likely to have a symmetric, bilateral distribution with a lower lobe predominance
• early phase -ground-glass opacities are the dominant pattern and reflect the presence of
alveolar septal edema and hyaline membranes
• The costophrenic angles are often spared.
• Honeycombing may be seen late in the disease.
• Features of AIP are similar to those of acute respiratory distress syndrome;
•

103. • diffuse, ill-defined areas of
• ground-glass opacity and
consolidation.

104. • shows illdefined consolidation at the lung bases.
• B.After 1 week, the patient is intubated and consolidation has progressed. The appearance is similar to
other causes of acute respiratory distress syndrome.

105. CT
• Areas of consolidation + : less extensive and limited to the dependent area of the
lung
• early phase- airspace consolidation results from intraalveolar edema and
hemorrhage.
• However, consolidations are also present in the fibrotic phase and then result from
intraalveolar fibrosis
• In the late phase of AIP, architectural distortion, traction bronchiectasis, and hon
eycombing - most striking CT features (more severe in the nondependent areas )
• This can be explained by the “protective” effect of atelectasis and consolidation on
the dependent areas of the lung during the acute phase of disease, which attenuate
the potential damage associated with mechanical ventilation

106. • Distribution (a),CT image (b), and CT pattern (c) of AIP. AIP has a basal predominance (red area in
a). CT shows airspace consolidation (dark gray areas in c), ground-glass opacities (light gray areas
in c), and bronchial dilatation (red areas in c)

107. • patchy bilateral ground-glass opacity and consolidation, which tend to be diffuse or patchy.
indistinguishable from other causes of ARDS.
• Abnonnalities are most severe in the posterior lungs
• Architectural distortion,traction bronchiectasis, and honeycombing may be seen as the disease progresses.

108. • HRO shows ground-glass
• opacity and consolidation.

109. • Exudative phase of AIP in a 22-year old man. High-resolution CT image shows bilateral
ground-glass opacities (arrowheads) and consolidation (arrow) in the dependent areas of
the lungs. The anterior zones of the lungs are relatively spared.

110. • Fibrotic phase of AIP in a 53-year-old woman who survived the acute phase of the
disease. CT image shows fibrotic changes with traction bronchiectasis and architectural
distortion predominantly in the nondependent areas of the lungs (arrow). A coexisting
right pleural effusion is seen (arrowhead).

111. • Treatment is largely supportive and consists ooxygen supplementation.
• Corticosteroids seem to be effective in the early phase of disease
• Nevertheless, the prognosis remains poor, with a mortality rate of 50% or more (3).
• Although recurrences of AIP have been described, most patients who survive the
acute phase of the disease later progress to lung fibrosis