Imaging of Small Airways Disease

Area of Science:

• Pulmonary Medicine
• Radiology
• Pathology

Background:

• Bronchiolitis is defined as a disease of the small airways.
• It can be classified by its cause (etiology) and microscopic appearance (histologic features).
• Understanding bronchiolitis is crucial for diagnosing various lung conditions.

Purpose of the Study:

• To describe the classification of bronchiolitis based on etiology and histology.
• To outline the characteristic computed tomography (CT) imaging findings associated with different types of bronchiolitis.
• To emphasize the importance of integrating imaging findings with clinical and pathological data for diagnosis.

Main Methods:

• Review of literature on bronchiolitis classification and CT imaging features.
• Description of CT findings such as centrilobular nodules, ground glass attenuation, tree-in-bud opacities, and mosaic attenuation.
• Discussion of how expiratory CT can reveal air trapping.

Main Results:

• Cellular bronchiolitis shows inflammatory cells in small airways and alveoli, appearing as centrilobular nodules on CT.
• Constrictive bronchiolitis involves luminal narrowing due to fibrosis.
• Direct CT signs include centrilobular nodules and tree-in-bud opacities; mosaic attenuation indicates air trapping, often worsened on expiratory scans.

Conclusions:

• CT imaging provides direct and indirect signs of small airway disease in bronchiolitis.
• Combining CT findings with clinical and pathological information improves diagnostic accuracy.
• Accurate diagnosis of bronchiolitis relies on a multidisciplinary approach.