CT-based lung ventilation metrics: reference ranges and pulmonary function test correlations in healthy individuals.

Area of Science:

• Radiology
• Pulmonary Medicine
• Medical Imaging

Background:

• CT scans with paired inspiration and expiration can assess regional lung ventilation.
• Normative reference values for CT-derived ventilation are currently undefined.
• Pulmonary function tests (PFTs) serve as the clinical standard for lung assessment.

Purpose of the Study:

• To establish reference values for pulmonary ventilation using CT.
• To compare CT-derived ventilation metrics with PFTs.
• To investigate the influence of demographic and anatomical factors on CT-derived ventilation.

Main Methods:

• Prospective study of 103 healthy adults undergoing spirometry-guided inspiratory and expiratory CT.
• Automatic lobe segmentation using TotalSegmentator.
• Voxel-wise ventilation quantified as relative air volume change, normalized to inspiratory lung volume.
• Comparison of CT-derived lung volumes (TLC, RV, VC) with PFT-derived values.
• Multivariable analyses of sex, age, height, lung region, and gravitational orientation effects.

Main Results:

• Included 91 participants (mean age 53 ± 12 years, 49 men).
• Mean CT-derived ventilation was 59.5% ± 8.5% (5th-95th percentile: 42.1-72.5%).
• CT-derived volumes showed strong correlations with PFT values but were systematically lower (CT-TLC: -13.8%, CT-RV: -2.5%, CT-VC: -20.8%).
• Ventilation decreased with age and increased with height.
• Higher ventilation observed in lower lobes and posterior lung regions.

Conclusions:

• CT-derived ventilation strongly correlates with PFT indices, providing a valuable functional lung assessment tool.
• Demographic factors (age, height) and anatomical location significantly influence ventilation distribution.
• Established normative data offer a reference framework for objective clinical interpretation of CT-derived ventilation.