Identification of Sentinel Lymph Nodes Using Contrast-Enhanced Ultrasound in Breast Cancer

Abstract

Sentinel lymph node (SLN) biopsy has become the standard of care in axillary staging of breast cancer patients who are clinically node negative as it reduces the morbidity of axillary nodal dissection. SLN biopsy using blue dye and radioisotopes have high identification rates but its limitations include anaphylaxis, disposal of radioactive waste, and potential second surgery in up to 35% of patients who show nodal metastases on SLN biopsy. Contrast-enhanced ultrasound (CEUS) has the potential for SLNs to be identified without the aforementioned risks. CEUS involves the administration of intravenous contrast agents containing microbubbles of perfluorocarbon or nitrogen gas. The bubbles greatly affect ultrasound backscatter and increase vascular contrast in a similar manner to intravenous contrast agents used in CT and MRI. It is safe and easily performed with no requirement for ionizing radiation and no risk of nephrotoxicity. Microbubbles are taken up by lymph nodes when injected directly into tissues, including sub-areolar injection in the breast cancer patient. This method may prove valuable in patients with ductal carcinoma in situ, where operative SLN biopsy remains controversial, and in women undergoing prophylactic mastectomies for high risk. This technique may also have a role after neoadjuvant chemotherapy where frequently there is fibrosis in the treated SLNs.

Study on Sentinel Lymph Node and Its Lymphatic Drainage Pattern of Breast Cancer by Contrast‐Enhanced Ultrasound

“…Hiroshi Ashiba et al 29 showed that the accuracy of CT in detecting SLN metastasis was 93.00% to 98.00%. Naresh Kumar Saidha et al 30 showed that the accuracy of CEUS in detecting SLN metastasis was 95.45%. The accuracy of SLN metastasis was similar between the two methods.…”

Diagnostic efficacy of sentinel lymph node in breast cancer under percutaneous contrast‐enhanced ultrasound: An updated meta‐analysis

“…Using this characteristic, different pulse coding techniques are used to selectively extract the nonlinear harmonic signal of microbubbles and filter out the linear fundamental signal generated by tissues, so as to realize real-time blood perfusion imaging of organs and tissues. 31 The At present, the gold standard of SLN identification in breast surgery is isotope tracer and the methylene blue staining method. 32 Compared with the two methods, contrast-enhanced ultrasound has the advantages of less trauma, safety and convenience.…”

“…Using this characteristic, different pulse coding techniques are used to selectively extract the nonlinear harmonic signal of microbubbles and filter out the linear fundamental signal generated by tissues, so as to realize real‐time blood perfusion imaging of organs and tissues. 31 The CEUS technique has been extensively applied clinically especially in the diagnosis of cancer and metastatic lymph nodes. Recent studies have shown that CEUS has great potential in the diagnosis of SLNs in breast cancer.…”

Pharmacokinetic parameters and radiomics model based on dynamic contrast enhanced MRI for the preoperative prediction of sentinel lymph node metastasis in breast cancer

“…Magnetic resonance imaging (MRI) has been widely used in the diagnosis and staging of breast cancer because of its advantages of non-radiation, high soft tissue contrast and functional imaging. Although studies have showed that MRI has superior performance than some other techniques such as ultrasound or mammography, its efficacy in identifying axillary lymph node status is unsatisfactory [10,11]. Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) can provide pharmacokinetic parameters, including semiquantitative and quantitative parameters, and is a sensitive technique that reflects the extent of tumor angiogenesis [12].…”