Linear atelectasis

Linear atelectasis (plural: atelectases), and also known as discoid or plate atelectasis refers to a focal area of subsegmental atelectasis that has a linear shape. Linear atelectasis may appear to be horizontal, oblique or perpendicular and is very common. It usually occurs as a consequence of subsegmental bronchial obstruction and can resolve as quickly as it occurs.

Terminology

Depending on its shape, linear atelectasis is also known as plate, discoid or band atelectasis(and historically as Fleischner lines on chest radiographs, but not on CT). 

Subsegmental vs linear atelectasis

There is confusion about the use of the terms "subsegmental atelectasis" and "linear atelectasis" (and their synonyms). From an academic point of view, the term linear atelectasis is reserved for atelectasis which appears primarily in the lung bases and is secondary to hypoventilation. Conversely, subsegmental atelectasis includes both linear atelectases and all other forms of atelectasis that do not involve a whole bronchopulmonary segment. In other words, every linear atelectasis is a subsegmental atelectasis, but not every subsegmental atelectasis is a linear atelectasis.

Pathology

Aetiology

• hypoventilatory change in patients who are not taking deep breaths ("splinting")
  • postoperative status
  • chest wall trauma such as rib fracture
  • pleuritic chest disease
• pulmonary embolism
• pneumonia 
• aspiration
• bronchogenic carcinoma

History and etymology

Fleischner lines were named after Felix Fleischner(1893-1969), an Austrian-American radiologist, who first described them in 1938.

See also

• atelectasis