An Optimized 3D-Printed Meta-Matching Layer To Enhance Transmission Through Calcified Plaques

This work presents one of the first demonstrations of a directly 3D-printed, meta-matching layer (MML) tailored for medical ultrasound frequencies (4 MHz) to improve imaging through calcified plaques. Designed using subwavelength microstructured unit cells and fabricated with high-resolution additive manufacturing, the MML provides a gradient acoustic impedance to reduce reflections and enhance transmission through highly reflective arterial plaque models. Initial designs revealed significant performance gaps between simulations and experiments due to neglected attenuation; a second, optimized design included loss and acoustic-solid interactions, showing strong agreement between numerical and experimental results. Quantitative ultrasound imaging confirmed improved transmission into the lumen and reduced back-reflection compared to conventional aberration layers. Despite the added thickness, the optimized MML exhibited lower attenuation in certain frequency bands and preserved the visibility of downstream vessel structures. This proof-of-concept study confirms the feasibility of 3D-printed metamaterial layers at MHz ultrasound frequencies for medical imaging applications. Limitations such as structural scattering artifacts and the use of homogeneous phantom models are acknowledged. Nonetheless, this preliminary work opens a promising path for patient-specific, add-on metamaterial devices to enhance vascular ultrasound imaging, warranting further investigation into material optimization, heterogeneous models, and integration with image processing techniques.