Title:CT Quantification of Interstitial Lung Abnormalities and Changes of Agerelated
Pathomorphology
Volume: 20
Author(s): Xin Li, Zhimei Gao, Zhenlong Zhu, Yonghui Yang, Hao Liu, Yan Li, Qi Jiao, Dianping You and Shujing Li*
Affiliation:
- The Department of CT and MRI, Children's Hospital of Hebei Province, Shijiazhuang, China
Keywords:
Interstitial lung abnormalities, Low-dose computed tomography, Semi-quantification, Aging lung, Chronic lung injury, CT signs.
Abstract:
Background:
Interstitial lung abnormalities (ILA) are associated with further disease progression, increased mortality risk, and decline in lung function in the
elderly, which deserves enough attention.
Objective:
The objective of this study was to quantify the extent of interstitial lung abnormalities (ILA) in a non-smoking asymptomatic urban cohort in China
using low-dose CT (LDCT) and to analyze the age-related pathological changes.
Methods:
We retrospectively analyzed clinical data and chest LDCT images from a cohort of 733 subjects who were categorized into 3 groups: 18–39, 40-59,
and ≥60 years old according to age. Furthermore, we selected 40 cases of wax-embedded lung tissue blocks archived after pulmonary bullectomy
and the same age groups were categorized. Four representative CT signs of ILA, including interlobular septal thickening (ILST), intralobular
interstitial thickening (ILIT), ground-glass opacity (GGO), and reticular shadow (RS), were semi-quantified based on the percentage of the affected
area. The scores and distribution of four CT signs of ILA were compared between different sex and age groups. The age-related pathological
changes were analyzed.
Results:
The ILA findings were found predominantly in the lower lobes and the subpleural region. The semi-quantitative scores of four CT signs in all
subjects under 40 were 0. However, in subjects over 40 years old, the scores gradually increased with age, although most of them remained low.
The size of the alveoli increased, the number of alveoli decreased, the alveolar septum became thinner, and the number of ATII cells increased with
age. A statistically significant difference was observed among the different age groups (χ2=50.624, P=0.033; χ2=80.000, P=0.043; χ2=33.833,
P=0.000; χ2=13.525, P=0.031). The macrophage population and the percentage of collagen fibers in the alveolar septum increased, while the
percentage of elastic fibers decreased with age. There was no significant difference among the different age groups (χ2=19.817, P=0.506;
χ2=52.419, P=0. 682; χ2=54.868, P=0.518).
Conclusion:
When the four CT signs mentioned above are in the upper central area, and the score has a medium or high score, it is crucial to determine the
underlying pathological causes. ILA may be the result of chronic lung injury.