High frame rate contrast enhanced ultrasound imaging of lymphatic vessel phantom

Contrast enhanced ultrasound (CEUS) shows great potentials for visualising lymphatic vessels and identifying sentinel lymph nodes (SLN) which aid the diagnosis of breast cancer. However, current CEUS imaging techniques have some limitations: 1) Nonlinear tissue artefacts result in false bubble signals and reduce the image contrast; 2) Low spatial and temporal resolution limits the amount of information that can be captured by CEUS; 3) The slow lymph flow makes Doppler based approaches less effective. These limitations have prevented the accurate visualisation of lymphatic vessels and SLN. This work demonstrates the potential of high frame-rate (HFR) CEUS in detecting lymphatic vessels, and investigates the effects of flow velocity and ultrasound pressure on HFR CEUS imaging of lymph vessels in terms of image contrast and bubble signal persistence over time. It is shown that under slow flow, ultrasound amplitude has significant impacts on both image contrast and signal persistence.