The alterations of pulmonary morphological parameters with aging: an observational study with quantitative computed tomography

<bold>Background:</bold> Lung aging is associated with morphologic and physiological changes that cause alterations in lung function. Quantitative computed tomography (QCT) can be a tool for quantifying pulmonary morphological parameters. <bold>Purpose:</bold> We aimed to analyze the physiological alterations of lung vessels and airways during aging with QCT based on the deep-learning algorithm. <bold>Methods:</bold> 1500 non-smokers (729 females, 45±14 years) who underwent chest low-dose computed tomography (LDCT) were retrospectively included. The participants were classified into three groups according to age: the young group (20-39 years old), the middle-aged group (40-59 years old), the elder group (≥60 years old). Pulmonary morphological parameters on LDCT were quantified with QCT and compared among three groups. <bold>Results:</bold> With advancing age, there were significant increases in large artery diameter, such as main pulmonary artery diameter and ascending aorta diameter (p<0.001), whereas, smaller pulmonary vascular parameters significantly reduced in elder group compared with young and middle-aged group(p<0.05) and were comparable between young and middle-aged groups(p>0.05). The fractal dimension and tortuosity of pulmonary vessels and airways were similar among three groups(p>0.05). <bold>Conclusion:</bold> QCT based on deep-learning algorithm is valuable for quantification of pulmonary morphologic changes with age. At the age of 60, there is a significant change of pulmonary small vascular parameters. Our findings highlight the important characters of age-related alterations in pulmonary structure and provide insights into the physiological changes that occur in the respiratory system as individuals age.