[Quantitative CT analysis technique for determining the extent of silica-induced fibrosis in silicosis].

Objective

To investigate the feasibility of computed tomography (CT) quantitative analysis in assessing the degree of silicosis fibrosis induced by silicon dioxide (SiO(2)) .

Methods

In March 2024, twenty specific pathogen-free (SPF) male C57BL/6J mice were randomly divided into a control group and a model group (n=10 per group). Each group was further subdivided into 28-day and 56-day subgroups (n=5 per subgroup). The model group received a single intratracheal instillation of 50 μl of sterile SiO? suspension at a concentration of 200 mg/ml via a non-surgical tracheal approach, while the control group received an equal volume of normal saline using the same method. At 28 and 56 days post-modeling, pulmonary function tests were performed, hydroxyproline (HYP) content in lung tissue was measured, and histopathological changes were evaluated by hematoxylin-eosin (HE) and Masson staining. Additionally, micro-CT scanning of lung tissue was conducted. Intergroup comparisons were performed using the t-test or a two-way analysis of variance (ANOVA) followed by post-hoc tests. Spearman rank correlation analysis was used to evaluate the correlation between CT quantitative parameters and Masson staining quantitative results.

Results

At 56 days, compared with the control group, the model group showed significantly lower tidal volume (TVb) and significantly higher respiratory frequency (f), expiratory time (Te), and inspiratory time (Ti) (all P<0.001). HYP concentration in lung tissue was also significantly increased (P<0.05). At 28 days, HYP concentration in the model group was significantly higher than that in the control group (P<0.01). The volume percentages of non-normally ventilated lung regions in the control and model groups were 30.54% and 50.99% at 28 days, and 37.40% and 61.60% at 56 days, respectively; all differences were statistically significant (P<0.01). Spearman rank correlation analysis revealed a significant positive correlation between the volume fraction of non-normally ventilated lung regions and Masson staining collagen fiber content in the model group (r(s)=0.68, P=0.035), whereas no statistically significant correlation was observed in the control group (r(s)=0.54, P=0.114) .

Conclusion

CT quantitative analysis demonstrates a favorable correlation with the pathological severity of silicosis fibrosis, suggesting that micro-CT may serve as a reliable non-invasive imaging tool for evaluating silicosis fibrosis.