Airway (Bronchial) Patterns

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Fig. 4.70 Drawings depict the patterns of atelectasis (by Sofia Echelmeyer)

tion of the right lower lobe with obliteration of the right hemidiaphragm and the right costophrenic angle. Also, the right heart border is becoming obscured. The CXR taken several hours later displays complete collapse of the right lung.

Pattern: Airway, complete obstruction.

Differential Diagnosis: RLL atelectasis from obstruction from blood, bullet fragments, or tooth (blood most likely since metal or calcification is not seen in the area of the bronchus). A blood clot was discovered and removed at urgent bronchoscopy.

Aspiration, potentially developing into pneumonia; however, post bronchoscopy CXR shows clearing after removal of blood.

Partial Obstruction

A good example of partial airway obstruction is bronchiolitis obliterans (BO) where air-trapping can be seen on expiration CT. This condition is uncommon; however, this can be seen post infection, especially in children, or post transplant. See Fig. 4.72 for inspiration/expiration HRCT demonstrating air-trapping in the expiration.

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Fig. 4.71a CT scout of head, neck, and chest showing a GSW to the mandible with the bullet in the trachea. Note developing RLL atelectasis

4 Abnormal Lung Patterns

Mandible Fx

Frag

RLL

Atelectasis

Fig. 4.71b CXR obtained 1 h after GSW showing

decreased visualization of the right hemidiaphragm with associated increasing density RLL

Airway (Bronchial) Patterns

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Fig. 4.71c CXR obtained in ICU 3 h after wound showing complete whiteout of right hemithorax with truncation of right mainstem bronchus. Note also shift in the trachea to the right. This is compatible with right lung collapse due to right mainstem bronchus obstruction

Fig. 4.71d CXR post bronchoscopy/removal of blood clot. Note the return of aeration to the right lung

Radiological Signs

Can also have increased lung volume (chronic air-trapping) overall.

Findings: Generalized hyperaeration, with additional localized air collections. Pattern: Airway, partial obstruction.

Differential Diagnosis

•Bronchiolitis obliterans

•COPD

•Centrilobular emphysema

•Pneumatoceles