Modeling and Simulation of Pulmonary Acoustic Signal and Imaging for Lung Function Assessment

Structural airway changes can be related to acoustic airflow resistance in various chronic lung disorders. However, acoustic imaging for pulmonary diagnosis has been challenging. This paper presents a study on lung function assessment with acoustic imaging through respiratory modeling and simulation and correlates acoustic lung images with pathologic alterations. The method combines wall thickness, inner radius, airway length, and tissue structure into mathematical modeling for pressure, wall elasticity, and airflow at each airway level. By modifying the airway wall thickness (AWT), we have demonstrated the airway resistance of healthy lungs and lungs with respiratory diseases. In addition, the correlation between increasing AWT and mean acoustic image intensity is established for characterizing the severity of the respiratory disease. Furthermore, a structural similarity index of 0.8762 was achieved between our model impedance acoustic image and reference lung sound acoustic image. This work can potentially be used for optimizing the number of acoustic sensors and their placement to obtain an accurate and frequent respiratory assessment.