Pulmonary patches

Could be due to

1-Pneumonia:

-Differentiated by clinical picture from infarction.

-Pneumonia is much more common than infarction.

-Complications of pneumonia are

*Pneumatocele which could be infected causing abscess, ruptured causing pneumothorax.

*Pleural effusion which could be infected causing empyema (enhanced wall contains air bubbles).

*Bronchiectasis and 

*Cavitary necrosis: 

*Cystic fibrosis:

Imaging findings

Central bronchiectasis is seen in almost all cases.

Bronchial wall thickening.

Peribronchial interstitial opacities.

Mucus plugging---Branching or nodular opacities.

Mosaic pattern(areas of hypertranlucency due to decreased perfusion)

2-Infarction:

3-Pulmonary sequestration:

-Non functioning lung parenchyma that do not communicate with tracheo bronchial tree.

-Has an anomalous arterial supply direct from aorta.

-Usually presents by recurrent infection(resistant to treatment), however, diagnosis is commonly made incidentally.

D.D. between it and pneumonia---pneumonia has an illdefined edge while sequestration is of sharply defined edge.