Numerical Investigation on the Acoustic Imaging of the Human Respiratory System and Manufacturing of the Synthetic Experimental Model

Almus, Furkan Ginaz
It is well known that physiological changes and diseases in the respiratory system affect the sound waves that form and propagate in the human body. The characteristics of these sound waves, such as frequency, amplitude, and phase, can contain critical and unique information about physiological changes and disorders. In this study, we aim to obtain a numerical model of the human respiratory system that can be used to understand the generation and propagation of acoustic waves within the human thorax and to employ acoustic imaging methods for the diagnosis of lung and respiratory system diseases. Two fundamental acoustic imaging methods, Conventional Beamformer and Matched-Field Processor have been used on the model with an exact geometry of the human respiratory system for the first time in the literature. The realistic numerical model of the human thorax has been obtained by processing the open-source Computed Tomography images through Materialise Mimics, which is a commercial image processing software. Acoustic imaging methods have been primarily investigated using the simple two-dimensional model, and findings were verified using the simple three-dimensional model and realistic numerical model. According to the literature, the selection of the steering vector is crucial in terms of the performance of the Conventional Beamformer. Therefore, we have examined four different steering vector formulations using the two-dimensional model. Also, we have evaluated the performances of the two different Matched-Field Processors using the same model. After comparing the different steering vector formulations and processors, we have applied the most robust and successful ones considering the localization results of the abnormal region within the lung to the simple three-dimensional and realistic numerical models. Numerical analyses of the models were performed using a finite element software, COMSOL Multiphysics. In addition to numerical investigation, the manufacturing methodology and process of the synthetic experimental respiratory system model that can be used for experimental validation have been presented.


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Citation Formats
F. G. Almus, “Numerical Investigation on the Acoustic Imaging of the Human Respiratory System and Manufacturing of the Synthetic Experimental Model,” M.S. - Master of Science, Middle East Technical University, 2022.