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

objectivesCT-derived assessment of regional ventilation is possible with paired inspiration and expiration scans. Normative reference values for CT-derived ventilation remain undefined. The aim of this study is to establish reference values for pulmonary ventilation using CT, with pulmonary function tests (PFTs) as the clinical standard. MATERIALS AND

methodsIn this prospective, single-center study (December 2022-April 2024), 103 healthy adults underwent spirometry-guided inspiratory and expiratory CT. Lobes were segmented automatically using TotalSegmentator. Voxel-wise ventilation was quantified as the relative air volume change between inspiration and expiration via nonlinear registration, normalized to inspiratory lung volume. CT-derived lung volumes were compared with PFT-derived total lung capacity (TLC), residual volume (RV), and vital capacity (VC). Reference intervals were reported as mean ± standard deviation and 5th-95th percentiles. Multivariable analyses assessed the effects of sex, age, height, lung region, and gravitational orientation.

resultsNinety-one participants (mean age, 53 ± 12 years; 49 men) were included. Mean ventilation was 59.5% ± 8.5% (5th-95th percentile, 42.1-72.5%). CT-derived volumes were systematically lower than PFT values but strongly correlated: CT-TLC (-13.8%, r = 0.89), CT-RV (-2.5%, r = 0.80), and CT-VC (-20.8%, r = 0.82). Ventilation decreased with age (p < 0.001) and increased with height (p < 0.05). Regionally, ventilation was higher in the lower lobes (p < 0.003) and posterior regions (p < 0.001).

conclusionCT-derived ventilation correlates strongly with PFT-indices but yields lower absolute values. Demographic and anatomical factors significantly influence ventilation distribution. These normative data provide a reference framework for clinical functional lung assessment. KEY POINTS: Question Can normative reference values for CT-derived regional lung ventilation be established, and how do these metrics relate to pulmonary function tests and anatomical/demographic factors? Findings Mean CT-derived ventilation was 59.5% ± 8.5% with strong pulmonary function test correlations. Ventilation exhibited significant regional heterogeneity and systemic variations by anatomical location, age, and sex. Clinical relevance Normative reference values enable objective classification of CT-derived ventilation, standardizing interpretation and reducing subjectivity. They facilitate earlier detection of regional dysfunction, quantitative phenotyping, risk stratification, longitudinal monitoring, and comparability with pulmonary function testing and other imaging.