Ultrasound super-resolution imaging enables multiparameter analyses of tumor angiogenesis during growth

Angiogenesis plays a crucial role in the process of tumor genesis. However, histological study limits the ability to repeatedly and invasively probe dynamic changes in tumor microvessels and functions over prolonged periods for patients. Ultrasound localization microscopy (ULM) has achieved noninvasive and non-radiation microvascular imaging with superior spatial resolution (8 µm). Here, we present 3D ULM imaging of microvasculature. The functional activity of blood vessels and vascular structure in different regions of the same tumor were quantified and compared during tumor growth. In the periphery and core areas of the tumor, we identified a rise vessel density at the beginning. During tumor growth, a slight but not significant increase in flow velocity is observed in both areas, and microvasculature in the periphery area consistently exhibits a more chaotic vascular network relative to the vessels in the core area. We emphasize the non-invasive application of ULM to monitor vascular dynamics and morphometric changes over wide fields during tumor growth. This unprecedented exploration of ultrasound super-resolution imaging strategy has notable potential for ultrahigh resolution assessment of treatment effect.