直肠癌；淋巴结转移；纳米炭；碘克沙醇；淋巴造影术

Abstract:

Objective：To investigate the feasibility and diagnostic value of iodixanol-carbon nanoparticles（CNPs） suspension to double tracing lymph nodes through preoperative CT lymphography（CT-LG） combined with intraoperative staining. Methods：Human col－orectal cancer cell suspension was injected under the rectal mucosa of nude mice to establish an orthotopic transplantation model of rectal cancer lymphatic metastasis. Thirty model mice were randomly divided into the iodixanol group（n=9） and the double tracer group（n=21）. The iodixanol solution under the rectal mucosa was injected in the iodixanol group，and the CNPs suspension was injected in the double tracer group. CT-LG was performed，followed by histopathological examination. Results：In the iodixanol group，the enhanced lymph nodes were observed at 5 min and 30 min. In the double tracer group，the enhanced lymph nodes were observed at 2 h，3 h，and 5 h. The best angiographic effect was obtained at 3 h. A total of 41 enhanced lymph nodes were detected by indirect CT-LG，of which 18 were in the iodixanol group and 23 in the double tracer group，consistent with the location of the biopsy lymph nodes. The sensitivity and positive predictive value of the cau－dal mesenteric lymph nodes（CLNs） metastasis in both groups were 100% when the uneven density，the irregular shape，and the filling defect were used as the diagnostic criteria. The sen－sitivity，specificity and accuracy of lymph node metastasis in the double tracer group and the iodixanol group were 78.6% vs. 81.8%，77.8% vs. 85.7%，and 78.3% vs. 83.3%，respectively. Conclusion：Indirect CT-LG with iodixanol-CNPs suspension can not only locate the lymph nodes and evaluate the metastasis before operation，but also assist in intraoperative biopsy or dissection with black-stained lymph nodes.