Development of a Method for Studying Biomechanical Properties of the Chest Wall Using Low-Frequency Elastic Waves

A laboratory hardware-software system (HSS) for studying local vibrational biomechanical properties of the chest and lungs was developed. The HSS includes a percussion vibrator with accelerometer, a second accelerometer, and a control block for delivering pulse input to the chest wall and detection of the wall reaction. The HSS provides controlled percussion of the chest wall and detection of acoustic reaction to these pulse inputs. Acceleration of the indenter of the percussion vibrator and acceleration of the second accelerometer adhered to the chest wall at a distance 2–10 cm from the site of percussion are measured. On the basis of the accelerations, we measured a frequency dependence of the modulus and phase of the local transfer function for vibration propagation in the chest wall of healthy volunteers. The group speed and the dependence of phase speed on frequency were estimated. The techniques for the measurement of local mechanical parameters of the chest wall using low-frequency elastic waves could be used for biomedical diagnosis of chest wall tissues.