Imaging of Small Airways Diseases

Area of Science:

• Pulmonary Medicine
• Radiology
• Pathology

Background:

• Small airways disease, also known as bronchiolitis, is a group of conditions characterized by inflammation and/or fibrosis of the bronchioles.
• Bronchioles are critical distal airways, typically invisible on standard imaging unless affected by disease.

Purpose of the Study:

• To review the anatomy of bronchioles.
• To discuss the differential diagnosis of cellular and constrictive bronchiolitis.
• To highlight key imaging features and differentiate from mimics.

Main Methods:

• Review of relevant literature on bronchiolar anatomy and pathology.
• Analysis of high-resolution computed tomography (HRCT) findings in small airways disease.
• Comparison of imaging features for differential diagnosis.

Main Results:

• Centrilobular nodules are the primary direct HRCT sign of bronchiolitis.
• Air trapping is the most significant indirect HRCT finding associated with bronchiolitis.
• Understanding key imaging features is crucial for distinguishing bronchiolitis from other conditions.

Conclusions:

• HRCT is essential for diagnosing small airways disease.
• Specific HRCT findings like centrilobular nodules and air trapping are key diagnostic indicators.
• Accurate differentiation from mimics improves patient management.