| Key
Facts |
- Inhomogeneous lung attenuation (ground glass) due to either patchy airspace obstruction with reduced ventilation or chronic vascular obstruction
- Decreased size of blood vessels in blacker lung helpful and points to vascular obstruction as cause
|
| Pattern |
- Look for abnormal airways, dilated or thickened walls as cause of airways obstruction
- Mosaic attenuation due to airways disease usually smaller (lobular) and more sharply defined
- Mosaic attenuation due to vascular disease less distinct and involve larger areas
- Expiratory scans usually to demonstrate air-trapping in airways disease
- "Head-Cheese sign"
|
| Differential
Diagnosis |
- Chronic PE
- Pulmonary hypertension
- Bronchiolitis obliterans
- Bronchiectasis
- Hypersensitivity pneumonitis
- Vasculitis
|
| References |
Stern EJ et al.: CT mosaic pattern of lung attenuation: etiologies and terminology. J Thorac Imaging 10:294-297, 1995.
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