Volumetric Ultrasound Localization Microscopy

Super-resolution ultrasound (SRUS) has evolved significantly with the advent of ultrasound localization microscopy (ULM). This technique enables subwavelength resolution imaging using microbubble contrast agents. Initially confined to 2-D imaging, ULM has progressed toward volumetric approaches, allowing for comprehensive 3-D visualization of microvascular networks. This review explores the technological advancements and challenges associated with volumetric ULM, focusing on key aspects such as transducer design, acquisition speed, data processing algorithms, or integration into clinical practice. We discuss the limitations of traditional 2-D ULM, including dependence on precise imaging plane selection and compromised resolution in microvasculature quantification. In contrast, volumetric ULM offers enhanced spatial resolution and allows motion correction in all directions, promising transformative insights into microvascular pathophysiology. By examining current research and future directions, this review highlights the potential of volumetric ULM to contribute significantly to diagnostic across various medical conditions, including cancers, arteriosclerosis, strokes, diabetes, and neurodegenerative diseases.