Prevalence of ground glass nodules in preschool children: a cross-sectional study.

Background: Following increased screening efforts and the use of thin-slice computed tomography (CT), there has been a considerable increase in the incidence of ground-glass nodules (GGNs) in adults. As a result, we have more and more treatments for ground-glass nodules in adults, but few in children. Most think development pattern of pulmonary GGNs is lung inflammation, tumor, or tuberculosis that are more related to acquired or environmental factors. By studying the incidence of pulmonary GGNs in preschool children, we sought to determine whether we had ground glass nodules in the lung before we were teenagers, but we didn't pay attention to them until later. If the hypothesis holds, we may change the cognition and treatment strategies of ground glass nodules. Even not, there are few epidemiological studies with big data that can fill this gap. Methods: We retrospectively collected the data of all preschool children who had undergone CT at the Children's Hospital of Zhejiang University School of Medicine from 2013 to 2020. These data were filtered according to the following exclusion criteria: severe artifacts, data with identical names to the original data; and patients without follow-up records (≥3 months). Inclusion criteria: must have undergone thin-slice CT (≤1.25 mm) at the first and last follow-up. Two thoracic radiologists with 5 years of experience and another senior one assessed the images. Results: There were a total of 13,361 cases after relevant exclusions, 311 patients were finally enrolled. Clinical features: age at diagnosis (year): 3.56±1.84, female: 147, male: 164, follow-up interval (month): 6.90±4.74, leukemia: 99, pneumonia: 21, lung cyst: 8, space-occupying lesions outside the lungs: 69, foreign body in respiratory tract: 6. After manual screening and reading, only 1 patient meets all requirements. The results showed that between 2013 and 2020, the incidence of GGNs that could be basically determined in the Children's Hospital of Zhejiang University School of Medicine was 0.32%. Conclusions: There have been few previous studies of GGNs in children, and based on our study, we found that there is still some associated morbidity for preschool children, it is rarely found when they are young.