Pulmonary parenchymal bands

Parenchymal bands are a HRCT finding. They can be commonly encountered among patients with asbestosis.

They are typically over 2 cm in length (up to 5 cm), 1-3 mm thick and run through the lung parenchyma and usually extend from a visceral pleural surface ⁶. They are formed in a number of ways ¹:

They are thought to reflect pleuroparenchymal fibrosis and are usually associated with distortion of the lung architecture.

• scars
• atelectasis
• thickening of interlobular septae of a number of adjacent secondary pulmonary lobules
• fibrosis of peribronchovascular interstitium

Parenchymal bands are encountered in a wide range of pulmonary diseases and represent one of the many end-stage fibrotic findings. To mention a few causes:

• asbestosis - found in 60% of patients ¹
• sarcoidosis ²
• silicosis ²
• systemic lupus erythematosus
• pulmonary fibrosis
  • ankylosing spondylitis ⁵
• sequelae of ARDS ⁴
• infections including
  • pulmonary paracoccidioidomycosis ³