Grading Bleomycin-Induced Pulmonary Fibrosis in ex vivo Mouse Lungs Using Ultrasound Image Analysis

Objectives: The aim of this study was to assess bleomycin-induced pulmonary fibrosis on ex vivo mouse lungs using ultrasound image grading and texture analysis. Methods: Excised mouse lungs were divided into 3 groups: control, mild fibrosis, and severe fibrosis based on the monitored indicators of health. B-mode ultrasound images were obtained via scanning the mouse lungs ex vivo. The surface smoothness, echo density, and angle of lesions or the lung margin were graded, and the imaging contrast, correlation, homogeneity, and entropy were assessed via texture analysis. Results: The grades of surface smoothness, echo density, and angle were statistically higher for the severe fibrosis group compared with those of the control and mild fibrosis groups (P <.05). In addition, statistically significant differences in the contrast, correlation, and homogeneity between mild and severe fibrosis groups were observed (P <.05). Conclusions: The results obtained in this study suggest that ultrasound image grading and texture analysis are valuable and meaningful methods for assessing pulmonary fibrosis in a bleomycin mouse model.