Value of Contrast-Enhanced Ultrasound for Evaluation of Cervical Lymph Node Metastasis in Papillary Thyroid Carcinoma

Abstract

The aim of the study was to evaluate the diagnostic value of contrast-enhanced ultrasound (CEUS) in distinguishing between benign and malignant cervical lymph nodes (LNs) in patients with papillary thyroid carcinoma (PTC). Two hundred and one cervical LNs (157 metastatic from PTC and 44 benign) were evaluated using conventional ultrasonography (US) and CEUS before biopsy or surgery. Histopathology was used as the gold standard. We evaluated the size, long axis/short axis ratio (L/S), fatty hilum, hyper-echogenicity, calcification, cystic change, peripheral vascularity and CEUS parameters for each lymph nodule. The CEUS parameters included enhancement type, homogeneity, perfusion type, ring enhancement, peak intensity (PI) index and area under the curve (AUC) index. Univariate analysis demonstrated that compared with benign LNs, malignant LNs more frequently had L/S < 2, absence of a fatty hilum, presence of hyper-echogenicity, presence of calcification, peripheral vascularity, hyper-enhancement, heterogeneous enhancement, centripetal perfusion, ring enhancement, PI index > 1 and AUC index > 1 on preoperative US and CEUS. Binary logistic regression analysis demonstrated that hyper-enhancement, centripetal perfusion, and ring enhancement are independent CEUS characteristics related to malignant LNs for their differentiation from benign LNs (all p < 0.05). Our study indicated that preoperative CEUS characteristics may serve as a useful tool to identify malignant cervical LNs from benign cervical LNs.

Contrast-enhanced ultrasound characteristics of preoperative central cervical lymph node metastasis in papillary thyroid carcinoma

“…According to the clinical guidelines, metastatic cervical lymph nodes often show a round shape, the absence of a fatty hilum, hyperechogenicity, microcalcifications, and cystic changes ( 6 , 34 ). In this study, metastatic CCLNs with a round shape (L/S <2) were found in 76.8% of malignant CCLNs and 50.8% of benign CCLNs, providing a sensitivity of 76.8% and a specificity of 49.2%, whose sensitivity was much higher than that of 37.0%–44.6% and the sensitivity was much lower than that of 70.0%–72.7% in the reported literature ( 6 , 20 , 34 ). This result indicates that lymph nodes of a round shape are more frequently imaged in the central cervical compartment than in the lateral cervical compartment.…”

“…Otherwise, more than half of the patients included in this study had Hashimoto’s thyroiditis, especially in the benign CCLN group, which is usually accompanied by swollen lymph nodes in the central compartment. A fatty hilum was absent in 97.4% of the malignant CCLNs and in 86.9% of the benign CCLNs, providing a sensitivity of 97.4% and a specificity of 13.1%, whose sensitivity was close to that of 91.1%–99.5% ( 19 , 20 , 34 ), and the sensitivity was much lower than that of 22.7%–51.0% reported in the literature ( 19 , 20 ). This result may contribute to the selection bias of many patients with Hashimoto’s thyroiditis included in this study.…”

“…The video of the CEUS was recorded for more than 30 s to image the lymph node via the vein lasting approximately 30 s. Compared with surrounding adjacent tissue enhancement, the contrast enhancement qualitative characteristics were classified as follows: hyper-, iso-, hypo-, or non-enhancement type (hyper-enhancement means as high as the thyroid tissue; hypo-enhancement means equal to or lower than the surrounding adipose tissue; iso-enhancement was between them), heterogeneous or homogeneous enhancement homogeneity, centripetal or centrifugal perfusion pattern, presence or absence of ring enhancement. Compared with surrounding adjacent adipose tissue enhancement, the contrast enhancement quantitative characteristics were classified as follows: peak intensity (PI) index >1 or ≤1, and area under the curve (AUC) index >1 or ≤1 ( 20 ).…”

“…Contrast-enhanced ultrasound (CEUS) has high sensitivity for vascularity compared with color Doppler imaging. CEUS has been applied to identify malignant and benign lymph nodes with good performance ( 19 , 20 ). However, most of the studies associated with the US features of metastatic lymph nodes are based on those of lateral cervical lymph nodes, and some of those reviews were not applicable to CCLNs ( 19 – 22 ).…”

Ultrasonography-Guided Thermal Ablation for Cervical Lymph Node Metastasis of Recurrent Papillary Thyroid Carcinoma: Is it Superior to Surgical Resection?

“…CEUS can show the changes of microvessels after thermal ablation and has become an effective method to evaluate local control of the tumor ( 34 , 35 ). It is of great significance to evaluate the local treatment effect as soon as possible after thermal ablation treatment, especially when the LNM is large or close to important tissues, so as to find the residual tumor tissue in time and carry out re-ablation treatment ( 11 , 25 , 31 , 36 ).…”