Intradermal Contrast-Enhanced Ultrasound Guided Fine Needle Aspiration Biopsy on Sentinel Lymph Nodes: Preoperative Diagnostic accuracy in Breast Cancers

Abstract

To explore the diagnostic value of pre-operative contrast-enhanced ultrasound (CEUS) combined with fine needle biopsy (FNA) of sentinel lymph nodes (SLNs) in breast cancer patients. The 63 consecutive patients with biopsy-proved breast cancer were enrolled. Two radiologists performed the procedure of axillary sentinel lymph nodes CEUS with intradermal microbubble injection. After the first enhancing axillary lymph node was localized, US-guided FNA was performed preoperatively. Methylene blue and indocyanine green were injected intradermally periareola to identify the SLN(s) during the operation. Enhancing patterns of SLN(s) and FNA results were compared with the final histopathological diagnosis. In 60 of 63(95.2%) patients, 73 SLNs were successfully identified by CEUS. SLNs CEUS enhancement pattern demonstrated as homogeneous, heterogeneous enhancement and no enhancement. 25 (34.2%) SLNs were enhanced homogeneously, and their FNA showed 23 negative and 2 suspicious, but all of them were negative on the final histopathologic examination. Heterogeneous enhancement was seen in 42(57.5%) SLNs. Among them FNA detected 9 metastatic SLNs, and the following histopathologic examination recognized 6 more of metastasis. All of the 6 unenhanced SLNs were involved both on FNA and histopathologic examination. If we use the heterogeneous enhancement or nonenhancement and FNA positive or suspicious as the diagnostic standard of SLN metastases, the sensitivity, specificity, positive predictive value and negative predictive value and accuracy were 71.4%, 100%, 100%, 89.7% and 91.8%. CEUS enhancement pattern combined with FNA proved to be a feasible and accurate procedure to recognize the metastatic SLNs of breast cancer patients with clinical negative axilla preoperatively.