The Effect of Sensor Array Design on Acoustic Imaging for Enhancing HFCWO Therapy

Innovative therapy with multiple independent actuators in high-frequency chest wall oscillation devices can be facilitated by targeting the detected nidus in the lung for higher therapy efficacy and efficiency. Acoustic imaging allows the detection of the nidus by converting the respiratory acoustic energy distribution to an image. However, the design of acoustic imaging systems, such as the sensor number, sensing diameter, and detectable nidus length has been typically empirical and yet to be examined. Hence, the impact of the sensor number and the sensors sensing diameter on the detectable nidus length via airway remodeling is examined in this study to provide quantitative design guidelines for new and existing acoustic imaging system. The nidus associated with mucus at each airway layer is simulated as localized high airway impedances to study the airway pressure and airflow characteristic through mathematical modeling by combining airway parameters such as, airway length, wall thickness, inner radius, and tissue structure. The nidus can be identified truthfully through the acoustic image output from the airway model. Nidus length resolution range of 73 mm to 4.35 mm via acoustic imaging can be detected with about 4 to 26,000 sensors, and with sensor sensing overlapping area between 0% and 95%. The resolution of the identified nidus length improves with the increase in sensor number.