Ultrasound Imaging: A Cornerstone of the Entire High-Intensity Focused Ultrasound Tumor Treatment Continuum.

High-intensity focused ultrasound (HIFU) has emerged as a safe and effective tumor treatment modality, harnessing thermal effects to induce tissue coagulation, cavitation effects to cause liquefaction, or a synergistic combination of both mechanisms. As a widely adopted diagnostic tool, ultrasound imaging plays an integral role throughout the entire HIFU treatment continuum, encompassing tumor diagnosis, localization, procedural navigation, real-time intraprocedural monitoring, post-treatment outcomes evaluation, and long-term clinical follow-ups. This is attributed to its real-time imaging capability, low cost, non-ionizing nature, deep tissue penetration, and satisfactory resolution and sensitivity. Conventional B-mode sonography has been extensively employed for guiding HIFU treatment, yet it is constrained by notable technical limitations. To address these issues, a range of innovative ultrasound imaging approaches have been developed. A narrative review of the literature was conducted to systematically examine the functional roles and performance characteristics of these emerging techniques and to explore their potential for clinical translation as an integrated, multi-functional single system. Evidence demonstrates significant improvement of these novel ultrasound imaging technologies across various stages of HIFU treatment, particularly in temperature imaging and tissue characterization. With continued technological advancements and systematic integration, ultrasound imaging is poised to play an increasingly crucial role in optimizing the safety and efficacy of HIFU tumor treatment.