Array measurement and imaging of sound transmission through the lungs.

Abstract

Non‐contacting scanning laser Doppler vibrometry (SLDV) was used to measure torso surface motion at an array of points caused by sound introduced into the lungs in human subjects. The SLDV serves as a gold standard as it does not have the complexity of surface contact dynamics. Additionally, a sensor array integrated into a compliant mesh fabric chair was constructed and tested as a less expensive and faster means of acquiring similar acoustic array data. Silicone gel‐coupled, piezoelectric contact sensors for the detection of subsurface acoustic sources at the skin surface were used in the array. Array measurements were processed to determine the response at each measurement point as a function of frequency up to 1.6 kHz. Acoustic images were generated indicating the amplitude level at each point relative to the amplitude measured at the suprasternal notch, which served as the reference input. The acoustic measurements illustrated the complexity of sound transmission in the human lung and chest. Expected attenuation over the scapulae and below the diaphragm was observed. There were other significant variations as a function of location and frequency; measurement results are discussed. [Work supported by NIH Grant # EB008373.]