Experimental Study On Ultrasound Contrast Agents Injected Subcutaneously For Diagnosing Sentinel Lymph Nodes Of Breast Cancer

Objective:To explore the feasibility of Rabbit Model Bearing VX₂ Breast Tumor of the sentinel lymph nodes(SLNs)and the lymphatics after subcutaneously injection of a ultrasound contrast agent(SonoVue)and determine if lymphatic US can be used to assess SLNs for the presence of metastatic infiltration.Methods:To establish a model of VX₂ breast carcinoma in rabbit:VX₂ breast carcinoma models were established in 28 rabbits by intramammary injection of tumor tissue mass suspension.Tumor sizes were measured every week after inoculation. Metastases to axillary lymph nodes were examined by palpation and ultrasonic inspection,and axillary lymph nodes sizes were measured too.The detection of Rabbits Model Bearing VX2 Breast Tumor of the sentinel lymph nodes(SLNs)and the lymphatics after subcutaneously injection of a ultrasound contrast agent(SonoVue):14 Rabbits Model Beating VX₂ Breast Tumor were injected subcutaneously with SonoVue directly superficial to the breast tumor.The SLNs were detected and observed by contrast enhanced ultrasound(CEUS).Then 99Tc-SC dynamic imaging was followed by injection of a blue dye and then dissection.Rabbit tumor were detected by routine pathologic examination (pathological type,tumor neovascul density marked with CD105);The successive pathological section of SLNs were detected after operation.The expression of CD44 in SLNs were studied with immunohistochemistry method.Result:1,VX₂ breast carcinoma models were established by intramammary injection of tumor tissue mass suspension:Breast tumor generated in all the animals,tumor proliferated most rapidly after 2nd～3rd weeks with the biological feature of squamous cell carcinoma.Swollen lymph nodes in axillares of 14 VX₂ breast carcinoma models could be loud after 4 weeks.Calcified lesions were seen at the 2nd～3rd week.Necrosis Or liquefaction appeared at the 4～6 weeks after implantation and at the 7th～6th week cavum formed.2,Twenty SLNs were detected in 14 rabbits model bearing VX₂ breast tumor and18 SLNs were correctly assessed using CEUS.Compared with dissection,the detecting rate of CEUS for SLNs was 80%(20/25).CEUS depicted metastases in SLNs with sensitivity,specificity and accuracy of 94.1%,66.67%,90%,respectively.Conclusion:1,Rabbits model beating VX2 breast tumor is suitable for making tumor model,tumor passage or doing experimental study on SLNs of breast tumor,because tumors grow fast and metastases in axillary lymph node were easy to generate after 4 weeks.2,Intramammary injection of tissue mass suspension is the best method.3,Detection of SLNs with lymphatic US compared favorably with that at lymphoscintigraphy in rabbits model bearing VX2 breast tumor,and SLNs can be characterized as benign or malignant with high diagnosis accuracy on the basis of enhancement of echogenicity as seen on contrast—enhanced ultrasound.