A Dual-Modal Sensor Fusion System for Bladder Volume Monitoring

Bladder volume monitoring (BVM) has attracted more and more attention in recent years for assessing bladder function in neurogenic bladder disorders. Among various noninvasive techniques, ultrasound (US) and bioimpedance (BI) have been frequently used in wearable technologies due to their relatively low cost and compact system size. The BI signal contains size-based information about the bladder volume from surficial tissue, while the US signal contains shape-based information as it can penetrate into the deep organs. However, the accuracy in both the US and BI system is far from satisfactory for practical usage. A dual-modal sensor fusion system has been proposed in this work. It incorporates both US and BI sensing in order to increase the system’s accuracy as their signals are complementary to each other. The hardware cost for the proposed dual-modal system is on par compared with the single-mode system as most of the electrical components, such as electrodes, amplifier, and analog-digital-converter can be reused in both modes. The proposed dual-modal system outperforms the US or BI mode alone in terms of accuracy in classifying bladder volumes ranging from 100 ml to 400 ml, making it an attractive approach for BVM applications.