Conformal multi-planar imaging enabled by a flexible ultrasound patch for high-curvature subcutaneous cysts

Flexible ultrasound patch (FUP) is widely used for wearable ultrasound because of conformal contact on large curvature skin surfaces such as breast. However, the acoustic performance of conventional FUPs with mechanical structures is limited due to redundant adhesive layers and copper film electrodes. We propose the dot-matrix ultrasound grid (DMUG) process and preparation of the 6.6 MHz flexible ultrasound patch(FUP), which conforms to the large curvature of the skin and features conformal and multi-section imaging. The matching surface of the high-performance dot element stacks (DESs) can be directly conformally coupled with the skin to enhance the transmission efficiency. The results show that FUP has a high -6 dB bandwidth of 81.51 % and low crosstalk of -61.9 dB. Axial and lateral resolutions are 0.38 mm and 0.55 mm, and the contrast is 1.91 at a depth of 22 mm for commercial phantom respectively. Finally, the imaging performance of FUP was verified on the challenging large curvature breast phantom, in which B-mode imaging can effectively distinguish solid breast cysts, mammary ducts, cyst boundaries and fine calcification structural features.