Sentinel lymph nodes (SLNs) are the first station of lymph nodes that extend from the breast tumor to the axillary lymphatic drainage. The pathological status of these LNs can predict that of the entire axillary lymph node. Therefore, the accurate identification of SLNs is necessary for sentinel lymph node biopsy (SLNB) to replace axillary lymph node dissection (ALND). The quality of life and prognosis of breast cancer patients are related to proper surgical treatment after the precise identification of SLNs. Some of the SLN tracers that have been identified include radioisotope, nano-carbon, indocyanine green (ICG), and methylene blue (MB). However, these tracers have certain limitations, such as pigmentation, radiation dangers, and the requirement for costly detection equipment. Ultrasound contrast agents (UCAs) have good specificity and sensitivity, and thus can compensate for some shortcomings of the mentioned tracers. This technique is also being applied to SLNB in patients with breast cancer, and can even provide an initial judgment on SLN status. Contrast-enhanced ultrasound (CEUS) has the advantages of high distinguishability, simple operation, no radiation harm, low cost, and accurate localization; therefore, it is expected to replace the traditional biopsy methods. In addition, it can significantly enhance the accuracy of SLN localization and shorten the operation time.
前哨淋巴结（SLN）是指从乳腺原发肿瘤到腋窝淋巴引流途径中的第一站淋巴结，这些淋巴结的病理状态可以预测整个腋窝淋巴结的情况。因此，准确识别SLN是前哨淋巴结活检（SLNB）替代腋窝淋巴结清扫（ALND）的关键。乳腺癌患者的生活质量和预后与识别SLN后的手术方式有关。目前常用的一些SLN示踪剂包括放射性同位素、纳米碳、吲哚菁绿（ICG）和亚甲蓝（MB）。然而，这些示踪剂都有一定的局限性，如色素沉着、放射性损害以及所需设备价格昂贵。超声造影剂所具有的简便性和安全性可以弥补上述示踪剂的一些不足。该技术也被应用到乳腺癌患者的SLNB，甚至可以初步判断SLN的状态。由于超声造影技术（CEUS）具有高识别率、易操作、无辐射、低成本、定位准确等优点，有望取代传统的活检方法。此外，它还可以显著提高SLN定位的准确性，并有效缩短手术时间。.
前哨淋巴结（SLN）是指从乳腺原发肿瘤到腋窝淋巴引流途径中的第一站淋巴结，这些淋巴结的病理状态可以预测整个腋窝淋巴结的情况。因此，准确识别SLN是前哨淋巴结活检（SLNB）替代腋窝淋巴结清扫（ALND）的关键。乳腺癌患者的生活质量和预后与识别SLN后的手术方式有关。目前常用的一些SLN示踪剂包括放射性同位素、纳米碳、吲哚菁绿（ICG）和亚甲蓝（MB）。然而，这些示踪剂都有一定的局限性，如色素沉着、放射性损害以及所需设备价格昂贵。超声造影剂所具有的简便性和安全性可以弥补上述示踪剂的一些不足。该技术也被应用到乳腺癌患者的SLNB，甚至可以初步判断SLN的状态。由于超声造影技术（CEUS）具有高识别率、易操作、无辐射、低成本、定位准确等优点，有望取代传统的活检方法。此外，它还可以显著提高SLN定位的准确性，并有效缩短手术时间。
Keywords: Breast cancer; Contrast-enhanced ultrasound (CEUS); Sentinel lymph node (SLN); Ultrasound contrast agent (UCA).