Optimizing image fidelity in a spherical array geometry for pulse-echo ultrasound and volumetric optoacoustic imaging

Spherical arrays are commonly used in volumetric optoacoustic tomography for optimal data acquisition. Yet, such a configuration poses challenges for integration with pulse-echo ultrasound used for image guidance, which relies on different signal acquisition and image formation strategies. A potential solution entails the incorporation of linear array segments into the spherical array to enable hybrid 3D optoacoustic and 2D ultrasound (OPUS) modes. This study aims to optimize ultrasound performance in a hybrid multi-segment spherical array for clinically interpretable images. Focusing on the independent and combined effects of image compounding, the number of consecutive emitting elements, and Richardson-Lucy deconvolution, quantitative analyses of phantom images showed marked improvements in image contrast and resolution. Clinical imaging of a healthy volunteer demonstrated that landmark structures could be effectively enhanced. This work establishes a practical framework for improving ultrasound imaging in OPUS, representing a significant step toward the clinical translation of optoacoustic imaging.