Abstract
BACKGROUND: This retrospective study aimed to investigate the computed tomography (CT) manifestations, short-term dynamic evolution features and quantitative lung CT analysis of inhalation lung injury induced by smoke bomb flare. METHODS: Eleven pediatric patients (aged 11 to 13) who inhaled the smoke of smoke bombs underwent several low-dose chest CT scans. The image characteristics and their dynamic changes were observed and quantitative CT values were analyzed. The quantitative CT indicators included lung injury CT score (LICTS), lung fibrosis CT score (LFCTS), mean lung density (MLD), normally aerated volume ratio (NAVR) and reductively aerated volume ratio (RAVR). Box-plot was used to analyze the dynamic changes of each indicator and Spearman statistical method was used to analyze the correlation between any two indicators. RESULTS: (I) In most cases, there were multiple consolidation and massive ground-glass opacities (GGOs) in the two lungs, which aggravated in the early stage and then gradually dissoluted in the later stage. LICTS was positively correlated with MLD (r=0.811, P=0.000), while it was negatively correlated with NAVR (r=-0.712, P=0.000). There existed interstitial fibrosis in the later stage, and LFCTS was positively correlated with RAVR (r=0.382, P=0.028). (II) In one case, the patterns were like layered cake, i.e., consolidation with air bronchus signs in the accumulation area, GGOs in the aforementioned area and normal lung in the top area. The patterns aggravated in the early stage and quickly dissolved in the later stage, and only a few residual fibrotic lesions existed on the final scan. (III) For severe cases, pneumomediastinum and subcutaneous emphysema aggravated in the early stage and then gradually dissolved in the later stage. CONCLUSIONS: The chest CT manifestations of inhalation lung injury induced by smoke bombs are predominantly GGOs and consolidation. They aggravate in the early stage and gradual dissolute in the later stage. CT quantitative values can contribute to evaluating the extent of this disease, and NAVR and RAVR can be used to assess pulmonary function.