Assessment of lingual sentinel lymph nodes metastases using dual-modal indirect CT/MR lymphography with gold–gadolinium-based nanoprobes in a tongue VX₂ carcinoma model

Abstract

Objective: To evaluate the capability of indirect computed tomography and magnetic resonance lymphography (CT/MR-LG) with gadolinium-loaded, polyethylenimine-entrapped gold nanoprobes (Gd-Au PENPs) for assessing lingual sentinel lymph node (SLN) metastasis in a tongue VX₂ carcinoma model.

Materials and methods: Seventeen rabbits were used to establish a metastatic cervical lymph node model by implanting VX₂ carcinoma suspension into the ventral tongue muscle. CT and MR images were acquired one hour after Gd-Au PENPs injection into the tongue submucosa bilaterally, on 1w (n = 4), 2w (n = 6) and 3w (n = 7) tumour-bearing rabbits after carcinoma transplantation. Then, the filling defects and enhancement features of the lingual SLN on indirect CT/MR-LG were assessed.

Results: The enhanced lingual SLNs were observed bilaterally in all rabbits using indirect CT/MR-LG. In total, 15 enhanced SLNs displayed oval or round shape with uniform density and no filling defects or only local small filling defects, and all nodes were metastasis-negative, while 19 enhanced SLNs demonstrated irregular morphologies with filling defects, non-uniform densities and unclear borders, of which 14 nodes were metastatic. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value when using SLN enhancement with irregular morphology, filling defects, non-uniform density and unclear border as diagnostic criteria for metastasis were 100%, 75.0%, 85.3%, 73.7% and 100%, respectively.

Conclusions: Indirect CT/MR-LG with Gd-Au PENPs can be used for the metastatic diagnosis of lingual SLN in tongue cancer.

Chinese abstract

目的：评估间接计算机断层扫描和用载有钆的由聚乙烯亚胺包埋的金纳米探针（Gd-Au PENPs） 进行的 磁共振淋巴造影（CT/MR-LG）对检测舌VX2癌模型中的舌前哨淋巴结（SLN）转移的能力。

材料与方法：通过将VX2癌症悬液植入17只兔子的腹侧舌肌来建立转移性颈部淋巴结模型。在癌症移植后一个星期（n = 4）, 两个星期（n = 6）和三个星期（n = 7）时, 带肿瘤兔的舌下黏膜双侧注入Gd-Au PENPs一小时后取CT和MR图像。然后, 评估间接CT/MR-LG上的舌SLN的充盈缺损和增强特征。

结果：使用间接CT/MR-LG, 在所有兔子双侧都观察到增强的舌前哨淋巴结。总共有15个增强得SLNs显示椭圆形或圆形, 密度均匀, 无填充缺陷或仅有局部小填充缺陷, 所有淋巴结均为转移阴性；而19个增强SLNs表现为不规则形态, 充盈缺损, 密度不均匀, 不清晰边界, 其中14个节点是转移性的。用不规则形态、充盈缺损、密度不均匀、边界不清晰的SLN增强 作为转移诊断标准时, 敏感性、特异性、准确性、阳性预测值和阴性预测值分别为100％、75.0％、85.3％、73.7％和100％。

结论：用Gd-Au PENPs的间接CT/MR-LG可用于舌癌内舌SLN的转移诊断。

Keywords:

• Indirect lymphography
• sentinel lymph node
• metastasis
• Gd-Au PENPs
• CT/MR

Disclosure statement

The authors declare that they have no competing interests.

Additional information

Funding

This project was supported by the Science and Technology Commission of Shanghai Municipality, China [no. 124119b0200, No. 15401971600 and No.17411962000] and the Shanghai Municipal Education Commission, China [no. 13ZZ008].