Lung volumes by computed tomography and plethysmography: are we measuring the same? CanCOLD study data

Area of Science:

• Pulmonary Medicine
• Radiology
• Medical Imaging

Background:

• Lung volume measurement is crucial for pulmonary function testing.
• Computed tomography (CT) derived lung volumes are established, but comparability with plethysmography in large cohorts is uncertain.

Purpose of the Study:

• To compare lung volumes measured by plethysmography and CT in a large cohort.
• To assess the comparability of total lung capacity (TLC) and residual volume (RV) measurements between the two methods.

Main Methods:

• The CanCOLD study involved 1235 participants (COPD, at-risk smokers, healthy controls).
• Lung volumes were measured using both plethysmography and CT (inspiratory/expiratory scans).
• Comparisons focused on TLC and RV between the two measurement techniques.

Main Results:

• Plethysmography consistently yielded higher TLC and lower RV compared to CT across all groups.
• Strong correlation was observed for TLC between methods, with a stable bias.
• Correlation for RV was low to moderate, with higher variability in differences.

Conclusions:

• Plethysmography and CT provide different values for TLC and RV.
• Results from plethysmography and CT lung volume measurements are not interchangeable.