目的：初步探讨碘克沙醇-纳米炭混悬液通过术前CT淋巴造影（CT lymphography，CT-LG）联合术中染色法双重示踪淋巴结的可行性及诊断价值。方法：采用人结直肠癌细胞悬液注射于裸鼠直肠黏膜下建立直肠癌原位移植淋巴转移模型。将30只模型鼠随机分为2组，碘克沙醇组9只，双重示踪组21只。碘克沙醇组在直肠黏膜下注射碘克沙醇溶液，双重示踪组则注射碘克沙醇-纳米炭混悬液，分别进行间质淋巴造影，然后进行组织学检查。结果：碘克沙醇组在5 min、30 min观察到强化淋巴结。双重示踪组在2 h、3 h、5 h观察到强化淋巴结，3 h可获得最佳造影效果。间接CT-LG检测到41枚强化淋巴结，其中碘克沙醇组18枚，双重示踪组23枚，与淋巴结活检的位置一致。用密度不均匀、形态不规则、有充盈缺损作为淋巴结转移诊断标准时，2组肠系膜根部淋巴结（caudal mesenteric lymph node，CLN）转移的灵敏度和阳性预测值均为100%；双重示踪组和碘克沙醇组淋巴结转移的敏感性为78.6% vs. 81.8%，特异性为77.8% vs. 85.7%，准确性为78.3% vs. 83.3%。结论：碘克沙醇-纳米炭混悬液间接CT-LG既可用于术前定位淋巴结和评估转移情况，又可黑染淋巴结协助术中活检或清扫淋巴结。
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.
