1. “Crazy-Paving” Pattern at Thin-
Section CT of the Lungs:
RadioGraphics 2003; 23:1509-1519

2. Introduction
Reported in infectious, neoplastic, idiopathic, inhalational,
and sanguineous disorder of the lungs
Characterized by scattered or diffuse ground-glass
attenuation with superimposed interlobular septal
thickening and intralobular lines

3. Infection
• Pneumocystis carinii pneumonia (PCP)
Neoplasm
• Mucinous Bronchioalveolar Carcinoma (BAC)
Idiopathic Disorders
• Pulmonary Alveolar Proteinosis (PAP)
• Sarcoidosis
Inhalation Disorders
• Lipoid Pneumonia
Sanguineous Disorders
• Adult Respiratory Distress Syndrome (ARDS)
• Pulmonary Hemorrhage Syndromes

4. eoplasm
Mucinous Bronchioalveolar Carcinoma (BAC)
iopathic Disorders
ulmonary Alveolar Proteinosis (PAP)
arcoidosis
halation Disorders
ipoid Pneumonia

5. Pneumocystis Carinii
• Symptoms: cough, dyspnea, low-grade fever
• Chest Radiograph:
– Bilateral, perihilar reticular and poorly defined ground-glass
opacities  alveolar consolidation
– Scattered ground-glass attenuation (interlobular septal
thickening)
• Histology: foamy nature of the alveolar exudates and thickening of
the alveolar wa&s by edema and ce&ular infiltrates

6. Mucinous Bronchioalveolar Carcinoma
(BAC)
Mucinous  mucin-producing columnar ce&s with
moderate nuclear atypia
Lepidic growth pattern through the airways and air spaces
with preservation of the lung architecture.
Symptoms: Bronchorrhea

7. Mucinous Bronchioalveolar Carcinoma
(BAC)
Chest Radiography:
i&-defined consolidation or ground-glass opacities occur
in a focal or multilobar distribution
Lymphadenopathy
Pleural effusion
Chest HRCT:
Numerous and alveolar consolidation and ground-glass
attenuation  crazy-paving pattern

8. Pulmonary Alveolar
Fi&ing of the alveoli by a proteinaceous material
Associated with an inflammatory response in the adjacent
interstitium
Most common in adults, 20-50 years old
Dyspnea and nonproductive cough
Less common: Pleuritic chest pain, malaise, low-grade fever

9. Pulmonary Alveolar
Radiography : bilateral, symmetric alveolar consolidation or
ground-glass opacity, particularly in perihilar or hilar
distribution ~ pulmonary edema
HRCT : diffuse ground-glass attenuation with superimposed
intra- and interlobular septal thickening
Diagnosis with bronchoalveolar lavage

10. Sarcoidosis
Development of noncaseating granulomatous inflammation
Parenchymal findings: irregular thickening of the
bronchovascular bundles and sma& nodules along vessels

11. Nonspecific Interstitial
Interstitial inflammation and fibrosis with temporal and
spatial uniformity
Does not fulfi& clinicopathologic criteria for usual
interstitial pneumonia, desquamative interstitial
pneumonia, or acute interstitial pneumonia
Chest Radiography: bilateral pulmonary opacities, mainly
localized in the middle and lower zones

12. Nonspecific Interstitial
Chest CT findings: ground-glass attenuation, bilateral and
symmetric with a tendency to subpleural and basal
predominance
Other findings: Consolidation and irregular reticular lines
superimposed on a background of ground-glass attenuation
Honeycombing is typica&y absent

13. Organizing Pneumonia
Past: bronchiolitis obliterans organizing pneumonia
Chronic inflammatory process characterized by focal plugs of
granulation tissue (Masson bodies) in the lumina of distal sma&
airways
Associated with intraalveolar foamy macrophages and interstitial
ce&ular response
Most cases are idiopathic (cyrptogenic organizing pneumonia)

14. Organizing Pneumonia
Associated with co&agen-vascular diseases, infection, and
toxic effect drugs (bleomycin, methotrexate,
cyclophosphamide, gold salts, topotecan, amiodarone)
Symptoms: cough, dyspnea, fever of several weeks, and
leukocytosis
Response to steroid therapy

15. Organizing Pneumonia
Radiography and CT: scattered and asymmetric
consolidation bilatera&y, and peripheral (> 50%)

16. Organizing Pneumonia
HRCT: subpleural and peribronchovascular consolidation,
crazy-paving pattern is uncommon

17. Exogenous Lipoid
Pulmonary disorder resulting ,om chronic aspiration or
inhalation of animal, vegetable, or petroleum-based oils or
fats
Predisposing factors: structural abnormalities, neurologic
defects, and chronic i&ness
Histopathologic: intraalveolar macrophages containing
abundant cytoplasmic lipoproteinaceous material within
‘normal’ alveoli

18. Exogenous Lipoid
Subacute manifestations: larger vacuoles within alveoli,
surrounded by macrophages, inflammatory infiltrates of
alveolar wa&s and interlobular septa
Risk factors: repeated episodes of aspiration
Symptoms: mild ever, shortness of breath, and chest
discomfort

19. Exogenous Lipoid
Chest radiograph: nonspecific, bilateral lower-lobe airspace
opacities, mixed alveolar and interstitial opacities, and
poorly marginated focal mass-like lesions mimic pulmonary
neoplasm

20. Exogenous Lipoid Pneumonia
Lipoid Pneumonia
HRCT:
consolidation characterized by low attenuation (-35 to -75
HU) lipid deposition
Geographic ground-glass attenuation associated with
interlobular septal thickening within areas of ground-
glass attenuation
Intraalveolar and interstitial accumulation of lipid-laden
macrophages and hyperplasia of tyoe II pneumatocytes in

21. Exogenous Lipoid
Diagnosis: Bronchoalveolar lavage, transbronchial biopsy,
or open lung biopsy combined with history of ingestion and
radiographic studies.

22. Adult Respiratory Distress Syndrome
(ARDS)
Pulmonary edema characterized by re,actory hypoxemia
and respiratory distress
Risk Factors: Shock, contusion, infection, sepsis, aspiration,
drug abuse, and inhalation of noxious substances
Diagnosis: impaired diffusion capacity (DLCO), reduced
compliance of the lung, and typical radiologic findings

23. Adult Respiratory Distress Syndrome
(ARDS)
Chest Radiography:
Bilateral homogenous pulmonary opacities
Cardiomegaly and upper-lobe diversion are usua&y
absent
Chest HRCT:
Bilateral consolidation and ground-glass attenuation
Reticular and linear attenuation

24. Adult Respiratory Distress Syndrome
(ARDS)
May progress to architectural distortion, consolidation with
bronchiectasis, and honeycombing
Histologic: Edema of the alveoli and perivascular spaces
with fi&ing of the alveoli by a protein rich fluid

25. Pulmonary Hemorrhage Syndromes
Wide spectrum of diseases:
Idiopathic pulmonary hemosiderosis
Wegener granulomatosis
Churg-Strauss syndrome
Goodpasture syndrome
Co&agen-vascular disease (SLE)
Drug-induced coagulopathy
Hemorrhage associated with malignancy

26. Pulmonary Hemorrhage Syndromes
Diffuse parenchymal bleeding:
Hemodynamic modification of capi&ary pulmonary blood
flow
Pathologic changes in the alveolar wa&
Symptoms: hemoptysis, dyspnea, and anemia
Diagnosis: Bronchoalveolar lavage or Fe content of alveolar
macrophages

27. Pulmonary Hemorrhage Syndromes
Occurs up to 2% patients with SLE, associated with
extrapulmonary manifestations like glomerulonephritis
42 to 66 % patients do not have hemoptysis
Chest Radiograph and HRCT: asymmetric acinar and ground-glass
opacities or attenuation and crazy-paving pattern

28. Conclusions
Crazy-paving pattern: scattered or diffuse ground-glass
opacities or attenuation with superimposed
interlobular septal thickening and intralobular lines
Limited differential diagnosis  CT manifestations
of many diverse entities
Knowledge of the etiology prevent diagnostic errors
Location of characteristics, additional radiologic
findings, history and clinical presentation can o-en be
useful in su.esting the appropriate diagnosis