Abstract: Obstructive bronchitis is a fibrotic disease of the lungs that occurs in response to inhalation of noxious gases, immune dysfunction and lung or bone marrow transplantation. Fibrosis is a pathological hallmark of obstructive bronchitis, and alterations in its mechanical properties play a key role in understanding the pathological progression of obstructive bronchitis. Due to the lack of studies related to the mechanical properties of obstructive bronchitis, little is known about the pathological mechanisms in this area. Therefore, in this paper, to address the above problem, photoacoustic remote sensing elastography was used to image the biomechanical properties of bronchial fibrosis. The results showed that the rise times of photoacoustic signals corresponding to normal bronchial tubes as well as bronchial tubes in the early, middle, and late stages of fibrosis were 113 ns, 107 ns, 96 ns, and 70 ns, respectively, and a short rise time resulted in a large elastic modulus; the elastic modulus of fibrotic bronchial tubes was larger than that of normal bronchial tubes, and the elastic modulus in the three stages of fibrosis increased sequentially from the early stage to the late stage. In this paper, the changes of bronchial mechanical properties during the process of obstructive bronchitis were investigated and the relative values of elastic modulus were extracted to propose a new reference for the graded diagnosis and prevention of obstructive bronchitis.
Key words: biological optics; photoacoustic imaging; elastic imaging; photoacoustic remote sensing; bronchial fibrosis
（Acta Laser Biology Sinica, 2025, 34(3): 239-245）