To explore the clinical value of contrast-enhanced ultrasound (CEUS) combined with virtual?touch?tissue?imaging?and?quantification (VTIQ) in the preoperative evaluation of sentinel lymph node (SLN) metastasis inbreast cancer.

Seventy-two patients with 72 SLNs admitted to the First Affiliated Hospital of Harbin Medical University from June 2019 to January 2020 were included in the study. All patients underwent surgical treatment to obtain pathological results. All patients underwent routine ultrasound, CEUS, and shear wave elastography before operation. According to the postoperative pathological results, SLNs were divided into either a metastatic group (n=21) or a non-metastatic group (n=51). Contrast-enhanced ultrasound mode and VTIQ shear wave velocity (SWV) of SLNs were compared between the two groups. ROC curve analysis was performed to compare the performance of CEUS, SWV, and combined diagnosis in predicting SLN metastasis in breast cancer.

The CEUS enhancement mode differed significantly between metastatic and non-metastatic SLNs (χ²=25.53, P=0.000), and the differences in the maximum, minimum, and average SWV of VTIQ between the two groups were statistically significant (t=7.79, 7.12, 8.75, P=0.000). The area under ROC curve (AUC) of CEUS for the diagnosis of SLN metastasis was 0.829, and the best cut-off value was 1.5, that is, type I enhancement mode suggested non-metastatic SLN and types II, III, and IV enhancement modes suggested metastatic SLN. The sensitivity, specificity, positive predictive value, and negative predictive value of CEUS were 85.71%, 70.59%, 54.54%, and 92.31%, respectively. ROC curves of maximum, minimum and average SWV for diagnosing SLN metastasis were drawn. The AUCs of maximum, minimum and average SWV for diagnosing SLN metastasis were 0.910, 0.873, and 0.937, respectively, and the best cutoff values were 3.06, 2.23, and 2.64 m/s, respectively. The sensitivity, specificity, positive predictive value, and negative predictive value of SWV were 76.19%, 94.23%, 88.89% and 90.74%. The sensitivity, specificity, positive predictive value, and negative predictive value of CEUS combined with VTIQ in diagnosing SLN metastasis were 95.24%, 96.08%, 90.91%, and 96.08%, respectively; the AUC was 0.957.

CEUS combined with VTIQ technique can improve the diagnostic efficiency for lymph node metastasis of breast cancer and provide a reliable basis for axillary lymph node assessment before breast cancer operation.