Quantitative imaging analysis detects subtle airway abnormalities in symptomatic military deployers

Area of Science:

• Pulmonary Medicine
• Radiology
• Military Health

Background:

• Military personnel deployed to Southwest Asia and Afghanistan face risks from inhalational hazards.
• Persistent respiratory symptoms in deployers often present with normal pulmonary function and qualitative HRCT.
• Quantitative HRCT imaging may reveal subtle airway abnormalities.

Purpose of the Study:

• To evaluate quantitative HRCT imaging markers for large and small airway abnormalities.
• To compare airway wall thickness, emphysema, and air trapping in symptomatic deployers versus controls.
• To assess the utility of these markers in detecting deployment-related lung disease.

Main Methods:

• Chest HRCT images from 45 controls and 82 symptomatic deployers were analyzed.
• Thirona Lung software quantified airway wall thickness (Pi10), emphysema (LAA%-950), and air trapping.
• Statistical analyses compared deployer and control groups and assessed correlations with pulmonary function.

Main Results:

• Deployers were younger, had higher BMI, and fewer smoking pack-years than controls.
• Spirometry results were not significantly different between groups.
• Quantitative HRCT showed significantly elevated emphysema (LAA%-950) and airway wall thickness (Pi10) in deployers, even after adjustments. Emphysema remained significantly higher in deployers.
• Air trapping was more common in controls, likely due to age and smoking differences.
• In deployers, LAA%-950 and Pi10 correlated with spirometric markers of obstruction.

Conclusions:

• Quantitative chest HRCT imaging identifies emphysema in deployers with asthma and distal lung disease.
• This imaging technique may be valuable for detecting and monitoring deployment-related lung disease.
• Quantitative HRCT offers insights in cases where spirometry is typically normal.