Plane Wave Imaging with Large-Scale 2D Sparse Arrays: A Method for Near-Field Enhancement via Aperture Diversity

In the context of a medical imaging application for preclinical research, specifically, erebrovascular imaging in small animals, this work examines the challenges of using a Large-Scale 2D ultrasonic array with 32×32 elements (96×96 wavelengths). The application imposes demanding requirements: very near-field operation, high spatial resolution, high frequency, high frame rate, and imaging in a highly attenuating medium. These needs, combined with current technological limitations, such as element size and constraints on the number of elements that can be driven in parallel, pose significant challenges for system design and implementation. To evaluate system performance, we use plane wave imaging as a reference mode due to its ability to meet high acquisition speed requirements. Our analysis highlights limitations in spatial coverage and image quality when operating the full aperture under planewave transmission constraints. To overcome these limitations, we propose a sparse aperture strategy. When integrated with advanced signal processing techniques, this approach improves both contrast and resolution while maintaining acquisition speed. This makes it a promising solution for high-performance ultrasonic imaging under the demanding conditions of preclinical research.