Three-dimensional ultrasound imaging: a review of the technology

Three-dimensional (3D) ultrasound imaging is now established across a wide range of clinical applications, offering real-time volumetric visualisation of anatomical structures while remaining low-cost, portable, and non-ionising. This topical review provides a comprehensive overview of 3D ultrasound technology, covering established clinical uses as well as emerging innovations that may shape the future role of ultrasound as a volumetric imaging modality. We begin by detailing the principal acquisition techniques, including freehand scanning, mechanically-steered probes, and matrix arrays. This is followed by a review of the current state of the art of both the hardware and software required for 3D ultrasound imaging. We then present a wide range of established clinical applications from a technological perspective including obstetrics, gynaecology, cardiovascular medicine, musculoskeletal imaging, radiation therapy, oncology and surgery. Although 3D ultrasound improves spatial context for diagnostics, reduces operator dependence and is less susceptible to out-of-plane motion, it remains largely a complementary tool to its two-dimensional counterpart. Key challenges persist, including system complexity, data throughput demands, and limitations in real-time rendering and analysis. Further advances in machine learning, miniaturised electronics, and open-source development are expected to drive broader adoption across both high- and low-resource settings.