Objective

To explore the impact of chest CT air bronchogram on decision-making regarding bronchoalveolar lavage（BAL）in children with Mycoplasmapneumoniae pneumonia（MPP）.

Methods

A total of 487 children with MPP who were diagnosed and treated at Capital Center for Children's Health，Capital Medical University between June 1，2023 and June 30，2024 were enrolled into this study.Based on the presence of air bronchogram within pulmonary consolidation lesions on the initial chest CT scan，patients were categorized into three groups：group 0（n=126，no air bronchogram within consolidation lesions），group 1（n=153，air bronchogram visible within consolidation lesions but extending to only approximately half of the lesion），and group 2（n=208，air bronchogram visible within consolidation lesions and extending to the peripheral areas）.General clinical characteristics，clinical observation indicators ［C-reactive protein（CRP）level at admission，incidence of rales，and length of hospital stay］，fiberoptic bronchoscopy findings（quantity of secretions，presence of mucus plugs，and cast formation），as well as follow-up imaging results （complete resolution，major resolution，and minor resolution），were compared among three groups.The study procedures were approved by the Ethics Committee of the hospital where the study was conducted （Approval No.SHERLLM2024024）.As this was a retrospective study，the requirement for informed consent was waived by the Ethics Committee.

Results

①There were no statistically significant differences in gender ratio and age among three groups （P ＞0.05）.②Comparative analyses of CRP levels at admission，incidence of rales，and length of hospital stay among three groups revealed statistically significant differences （P＜0.05）.The incidence of rales and the length of hospital stay showed an increasing trend with higher imaging grades，respectively（χ2_trend=96.39，100.49；P＜0.001）.③Comparative analyses of the amount of secretions，positive rate of mucus plugs，and incidence of signs of cast formation among three groups showed statistically significant differences （P＜0.001）.The amount of secretions decreased with higher imaging grades（χ²=273.54，P ＜0.001），and the positive rates of mucus plugs and signs of cast formation significantly decreased as imaging grades improved，respectively（χ²_trend=112.94，70.96；P＜0.001）.④Follow-up chest CT performed 7-10 days after the initial examination demonstrated statistically significant differences in the degree of lesion absorption among three groups（χ²=186.82，P ＜0.001），with a significant trend of greater lesion absorption associated with improvement in imaging grade.

Conclusions

The chest CT air bronchogram grading method can serve as a reference for decision-making regarding the use of BAL in children with MPP.