Variable curvature flexible transducer for abdominal expandable-imaging

Expanding the imaging field of view (FOV) of medical ultrasound transducers will be more effectively detect pathological behaviors of tissues or organs. Conventional rigid transducers can be realized by increasing the number of array elements or the curvature, however, the imaging aperture is fixed by the original size and shape during the manufacturing process. This paper presented a 128-element, 3MHz flexible curvature abdominal array (FCAA) with the goal of dynamically expanding the FOV within a 120° range. The piezoelectric stack was divided into small pitches through a double-cut process, and two-component viscoelastic substrates (TCVSs) are filled between adjacent array elements to generate tensile and compressive stresses during decomposition deformation. A 3D printed push-pull device provides sufficient mechanical support, resulting in a conformal minimum curvature radius of 46mm. The innovative rigid-flexible composite backing layer was used to balance mechanical flexibility and high bandwidth (BW) of-6dB ~ 67.6 %. The results showed that the axial and lateral resolutions of the commercial phantom line target are 0.35mm and 0.77mm respectively, and the axial and lateral resolutions of FOV 120° are 0.36mm and 1.02mm respectively. The imaging performance of FCAA was verified by B-model imaging of the kidneys, intestines, uterus and bladder of volunteers with different BMI. In addition, the 5mm renal artery phantom verified the Doppler imaging function of FCAA. All the results demonstrated that FCPA has great potential clinical value in abdominal ultrasound and gynecological examination.