超声分子靶向造影检测甲状腺乳头状癌前哨淋巴结转移的基础研究

The incidence of papillary thyroid carcinoma (PTC) is increasing. 28%-60% of PTC invades the cervical lymph nodes. Surgery is the first choice for the treatment of PTC. The detection rate of central compartment lymph node micrometastasis by ultrasound preoperatively is low. To avoid the lack of treatment, prophylactic central compartment neck dissection is used traditionally. Actually, proportion of central compartment neck dissection with negative findings ranges from 57.6-84.8%, and that excessive surgery causes unnecessary harm for the patients.. Previous studies showed that contrast-enhanced ultrasound is a good method to visualize the sentinel lymph node (SLN), while it is not good for the diagnosis of SLN metastasis. Puncture eluent tests used commonly in clinic confirmed that thyroglobulin (TG) is a high specificity index for the diagnosis of lymph nodes metastasis from PTC. In this study, a novel targeted microbubble preparation technique will be used to carry TG antibodies. The effects of dual targeted contrast agent enhancement ways will be known by the tests in vitro and in vivo. Canocarbon will be injected under the guide of ultrasound to mark the SLN in order to remove it accurately during operation. The mechanism of SLN metastasis from PTC and the application value of targeted CEUS will be clarified by the basic and clinicopathologic studies. Accurate diagnosis of SLN metastasis before surgery will be helpful to decide the treatment schedule, and that will reduce the overtreatment and undertreatment, and provide reliable support for the minimally invasive ablation therapy.

甲状腺乳头状癌（PTC）的发病率居高不下，有28-60%的淋巴结转移。PTC的首选治疗方法为手术，因术前超声对中央区微小转移淋巴的检出率低，为避免治疗不足，传统多进行预防性区域淋巴结清扫，事实上清扫阴性率高达57.6%-84.8%，对多数患者造成不必要的伤害。.前期研究显示超声造影可用于显示前哨淋巴结(SLN)，但是诊断转移的准确率不高，临床常用的穿刺洗脱液检测法已证实甲状腺球蛋白（TG）是诊断PTC转移淋巴结的高特异性指标，本项目将采用新型靶向微泡制备技术，携载TG抗体，通过体外、体内实验明确双重靶向造影剂的显影效果，使用超声引导下纳米碳前哨淋巴结内注射标记，指导术中准确切除，通过基础及临床病理研究，明确PTC患者SLN的转移机制及靶向造影的应用价值。SLN是否转移的准确诊断将合理指导治疗方案的制定，减少过度治疗及治疗不足，并使微创消融治疗有据可依。

课题组针对甲状腺乳头状癌（PTC）前哨淋巴结的术前诊断做了一系列相关研究，逐层深入，并获得了有效的结果。具体如下：（1）颈部淋巴结转移风险的评估与预测。基于中央区淋巴结转移的危险因素建立了中央区淋巴结转移的量化模型，根据模型对评分高的PTC患者可推荐行中央区淋巴结清扫术，并得出PTC的常规超声及超声造影特征与颈部淋巴结转移具有相关性。相关结果发表2篇SCI论文及多篇中文论著。（2）PTC颈部前哨淋巴结的术前诊断。现今，前哨淋巴结的定位主要依靠外科术中示踪判断，术前诊断手段缺乏，基于此，本项目首先进行了动物实验，通过不同造影剂，不同注射位置的对比研究，最终选取全氟丁烷（sonozoid）作为示踪剂，采用腺体中部单点小剂量注射的方法进行检查，获得了高质量的CEUS图。后续开展前瞻性临床病例研究。得出以下结果：1）80%的患者中央区最早显影，15%的患者侧区先显影，0.5%的患者中央区与侧区同时显影。2）经淋巴管CEUS时，淋巴结的增强特点有四种情况，分别是均匀增强，环状增强，不均匀增强及无增强。.其中，均匀增强为正常淋巴结表现，规则环状增强多见于良性反应性增生性淋巴结，不规则环状增强、不均匀增强及无增强多见于恶性淋巴结。3）与常规超声相比，经淋巴管CEUS对颈部淋巴结转移的诊断具有明显优势（ROC曲线下面积：0.925 Vs 0.831）(P=0.04)。4）对于颈部不同分区的淋巴结，经淋巴管CEUS 对于IV区(76.92% VS 66.67%)及VI区 (96.23% VS 86.79%)淋巴结的诊断准确率明显好于常规超声，特别是VI区（中央区），可起到弥补作用。 相关结果已发表1篇中文论著。（3）携带甲状腺球蛋白抗体（TG）的靶向造影剂制备及检测。采用亲和素-生物素连接法，将生物素化的TG靶向连接于生物素化的全氟丁烷微泡上，制备后外观呈白色混悬液、不透明，微泡稳定性好，与抗体结合率高。体内实验显示寻靶显影能力良好，较对照组增强持续时间长。