Thin-section CT detection of emphysema associated with bronchiectasis and correlation with pulmonary function tests

Area of Science:

• Pulmonary Medicine
• Radiology
• Respiratory Physiology

Background:

• Bronchiectasis is a chronic lung condition characterized by airway dilation.
• Emphysema involves damage to the air sacs in the lungs.
• The relationship between these two conditions and their impact on lung function is not fully understood.

Purpose of the Study:

• To determine the prevalence of emphysema in patients diagnosed with bronchiectasis using thin-section CT scans.
• To correlate CT findings of emphysema with pulmonary function test (PFT) results.
• To identify if a specific PFT profile is associated with co-existing emphysema in bronchiectasis patients.

Main Methods:

• Retrospective analysis of 90 patients with bronchiectasis who underwent both thin-section CT and PFTs.
• Development of a CT scoring system to assess bronchiectasis severity/extent and emphysema extent.
• Independent review of CT scans by two radiologists, with consensus for final interpretation.
• Correlation of CT findings with PFTs including FEV1, FEV1/FVC, TLC, RV, and DCO/VA.

Main Results:

• Emphysema was detected on CT scans in 45% of patients, predominantly in segments affected by bronchiectasis.
• The extent and severity of bronchiectasis correlated with the presence of emphysema.
• Only 20% of patients with CT-evident emphysema showed functional evidence of emphysema.
• Patients with CT-identified emphysema exhibited significantly higher airflow obstruction and air trapping, and reduced diffusing capacity, but normal DCO/VA.

Conclusions:

• Emphysema is highly prevalent in patients with bronchiectasis.
• Pulmonary function tests often fail to detect emphysema in these patients.
• The presence of emphysema, potentially linked to the inflammatory process of bronchiectasis, may contribute to increased airway obstruction.