Fig. 1

CEUS tracing the SLN. a,b An intradermal injection of 1 mL UCA at 3 and 6 o ‘clock and a subcutaneous injection of 1 mL UCA at 9 and 12 o ‘clock of the mammary areola region was performed following disinfection; c The injection site was then massaged gently to ensure adequate absorption of the UCA by the lymphatic vessels; d 360° scanning of the areola area was performed to detect enhanced lymphatic vessels and trace the enhanced lymph nodes along the enhanced lymphatic vessels; e 0.1ml prepared 1:10 diluted carbon nanoparticles was injected into the first SLN site in CEUS; f The lymphatic vessel routes as well as the lymph node location were marked using a marking pen