Lung Sliding Detection in M-Mode Using Wearable Ultrasonic Sensor: An In-Vivo Feasibility Study

Pneumothorax (PTX) is the abnormal accumulation of air in the pleural space which causes the lung to collapse. The detection of the presence or absence of lung sliding (LS) in lung ultrasound motion-mode (M-mode) images can be used to rule out or diagnose PTX, respectively. This study investigates the detection of LS in M-mode images captured using a wearable ultrasonic sensor (WUS) with unfocused ultrasound plane waves. Preliminary in-vivo experiments show that the seashore sign (indicating the presence of LS) from the lung region and the pseudo-barcode sign from the chest wall region can be observed in M-mode images acquired using the WUS. The pseudo-barcode sign resembles the barcode sign (indicating the absence of LS) from the lung region. Based on gray-level co-occurrence matrix texture features, a linear support vector machine was able to perfectly differentiate between the seashore sign and the pseudo-barcode sign. This demonstrates that the WUS has potential for cost-effective, long term, and continuous monitoring for PTX.