Sound transmission in the chest under surface excitation: an experimental and computational study with diagnostic applications

Abstract

Chest physical examination often includes performing chest percussion, which involves introducing sound stimulus to the chest wall and detecting an audible change. This approach relies on observations that underlying acoustic transmission, coupling, and resonance patterns can be altered by chest structure changes due to pathologies. More accurate detection and quantification of these acoustic alterations may provide further useful diagnostic information. To elucidate the physical processes involved, a realistic computer model of sound transmission in the chest is helpful. In the present study, a computational model was developed and validated by comparing its predictions with results from animal and human experiments which involved applying acoustic excitation to the anterior chest while detecting skin vibrations at the posterior chest. To investigate the effect of pathology on sound transmission, the computational model was used to simulate the effects of pneumothorax on sounds introduced at the anterior chest and detected at the posterior. Model predictions and experimental results showed similar trends. The model also predicted wave patterns inside the chest, which may be used to assess results of elastography measurements. Future animal and human tests may expand the predictive power of the model to include acoustic behavior for a wider range of pulmonary conditions.

Experimental and computational studies of sound transmission in a branching airway network embedded in a compliant viscoelastic medium

“…Simulations were compared to published results for mice and used in part to calculate a preliminary acoustic damage threshold curve for humans as a function of frequency. Peng et al [17] conducted wide frequency band percussion studies on human and pig chest. Computational models of the upper torso were validated by comparison with experiment measurements.…”

Sound transmission in porcine thorax through airway insonification

“…X-ray computed tomography (CT) provides limited contrast for soft biological tissues and also introduces potentially harmful ionizing radiation. Due to these limitations, a preliminary study that utilizes noninvasive measurement of external mechanical wave motion (sound and vibration) for lung injuries was performed in dog and porcine subjects [30, 40]. The study suggested that this method may provide information about lung mechanical property changes, which may have diagnostic value.…”

A comprehensive computational model of sound transmission through the porcine lung

“…[3][4][5][6] Indeed simultaneous, multi-sensor auscultation methods have been developed to "map" sounds on the thoracic surface by several groups. 5,[7][8][9][10][11] Also recently the phase contrast-based technique known as magnetic resonance elastography (MRE) has been applied to the lungs in pilot studies with limited success. [12][13][14][15] MRE seeks to provide a map of the viscoelastic properties within the region of interest that will affect the shear wave motion that MRE measures.…”