A novel contrast imaging method could effectively assess lymphatic involvement in patients with medullary thyroid carcinoma (MTC) and other thyroid neoplasms, according to a study recently published in Frontiers in Bioengineering and Biotechnology.

“Microbubble contrast agent SonoVue is a valuable imaging contrast medium for thorough preoperative lymphatic mapping in patients with thyroid carcinoma, including the lymphatic drainage region, the detection of [a sentinel lymph node], and the diagnosis of [lymph node metastasis],” the authors wrote.

This observational study included 55 patients with 62 diagnosed thyroid malignancies. The vast majority (n=59) were papillary thyroid carcinomas, and 3 were MTCs.


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The microbubble contrast agent correctly identified the lymphatic drainage compartment in all cases. Region VI was the most frequently involved in 93.55% of the tumors, followed by regions III, IV, and II involved in 62.90%, 48.39%, and 4.84% of tumors, respectively. Only 2 cases with pathologically proven lymph node metastasis did not demonstrate a positive sentinel node with this technique.

The perfusion defect signaled lymph node metastasis more frequently in 54.17% of the cases. No perfusion was detected in 33.33% of tumors, and interrupted lymphatic vessels were noted in 14.58%.

Most thyroid nodules were in the inferior lobes (45.16%), closely followed by the upper lobes in 41.94% of the cases, and lastly, in the isthmus in 12.90%. The researchers identified 84 lymph nodes, the majority of them (71.43%) in the central cervical compartment and the remaining 28.57% in the lateral compartments. The microbubble contrast agent achieved diagnostic accuracies of 86.67% and 91.67% in the central and lateral compartments, respectively. More than half of the nodes (57.14%) showcased thyroid carcinoma metastasis.

This technique seems promising for preoperatively diagnosing lymph node metastasis in patients with MTC and other thyroid neoplasms. Regardless, more research and adjustments are warranted to overcome limitations.

“[Lymphatic contrast-enhanced ultrasound] with SonoVue alone has limitations of false negatives when there is lymphatic vessel obstruction and may need to be combined with other ultrasound modalities,” the authors noted.

Reference

Chen L, Dong B, Jiang L, et al. Microbubble contrast agent SonoVue: an efficient medium for the preoperative lymphatic mapping of thyroid carcinoma. Front Bioeng Biotechnol. Published online December 8, 2022. doi:10.3389/fbioe.2022.1077145