Zhang, L.*, Marcus, C.*, Lin, D.*, Mejorado, D., Schoen Jr, S. J., Pierce, T. T., Kumar, V., Fernandez, S. V., Hunt, D., Li, Q., Shuvo, I. I., Sadat, D., Du, W., Edenbaum, H., Jin, L., Liu, W., Li, F., Eldar, Y., Chandrakasan, A. P., Samir, A., Dagdeviren, C.†, “A Conformable Phased-Array Ultrasound Patch for Bladder Volume Monitoring”, Nature Electronics, 2023.

Abstract

Ultrasound can be used to image soft tissues in vivo for early diagnosis and monitoring of disease progression. However, conventional ultrasound probes are rigid, pressure-required, and operator-dependent. Conformable transducers have been proposed, but they lack the efficiency of element localization and spatial resolution during mechanical deformations for effective diagnostic imaging. Here, we report a conformable ultrasound bladder patch that is based on multiple phased arrays embedded in a stretchable substrate and can provide mechanically robust, conformable, and in vivo volumetric organ monitoring. The phased arrays are fabricated using Sm/La-doped Pb(Mg1/3Nb2/3)O3-PbTiO3(Sm/La-PMN-PT) ceramics as the piezoelectric material, which offers superior properties (d33= 1,000 pC/N, εr= 7,500,k33= 0.77), compared with conventional piezoelectric ceramics. We used the conformable ultrasound patch in a pilot clinical study of bladder monitoring. Bladder volume estimation with the patch is comparable (relative error of 3.2 ± 6.4% and 10.8 ± 8.2%, with and without ultrasound gel, respectively) to that obtained using standard clinical ultrasound equipment, while not requiring manual translation or rotation by an operator.