Computed tomographic-based quantification of emphysema and correlation to pulmonary function and mechanics

Area of Science:

• Pulmonary Medicine
• Radiology
• Medical Imaging Analysis

Background:

• Computed tomographic (CT) indices of emphysematous lung destruction can reveal differences in disease pathogenesis and aid in classifying Chronic Obstructive Pulmonary Disease (COPD).
• Limited published data exists comparing the performance of various radiographic analysis techniques for emphysema assessment in clinical settings.

Purpose of the Study:

• To evaluate multiple quantitative and semi-quantitative methods for assessing emphysema burden on CT scans.
• To compare the predictive ability of these CT-based methods for lung mechanics and function.

Main Methods:

• Automated densitometric analysis of 1094 CT scans from the National Emphysema Treatment Trial.
• Visual grading of emphysema by trained radiologists on high-resolution CT scans.
• Correlation with full pulmonary function test results and lung static recoil measurements.

Main Results:

• A broad spectrum of emphysematous lung destruction was observed across the CT scans.
• Univariate correlations between CT findings and lung function measures demonstrated modest strength.
• No single CT scan analysis method consistently outperformed others in predicting lung function.

Conclusions:

• CT-based quantification of emphysema burden is a weak predictor of lung function and mechanics in severe COPD.
• No uniformly superior method was identified for CT-based emphysema analysis.
• CT-based emphysema quantification may offer complementary phenotypic information to augment pulmonary function testing in COPD characterization.