Detection of sentinel lymph node using contrast-enhanced agent, Sonazoid^™, and evaluation of its metastasis with superb microvascular imaging in oral and oropharyngeal cancers: a preliminary clinical study

Abstract

Background: In sentinel lymph node (SLN) biopsy for head and neck cancers, the radioisotope method has been the gold standard. However, this method has several problems, such as unavoidable radiation exposure and requirements of expensive equipment.

Aims/Objectives: To overcome these problems, we evaluated the contrast-enhanced ultrasonography (CEUS)-guided SLN-detection method, and predicted the SLN metastatic status using novel ultrasound technology, superb microvascular imaging (SMI).

Methods: Ten patients (6 with oral and 4 with oropharyngeal cancers) without neck lymph node metastasis were enrolled in this study. Ultrasound contrast agent, Sonazoid^™, was infiltrated into the mucosa at the primary site to observe the lymphatic ducts and SLNs in the neck field. The detected SLNs were examined for blood flow using SMI to categorize the SLNs metastases-positive or negative.

Results: SLNs were successfully detected in 8 out of 10 cases. In 7 out of the 8 cases, in whom SLNs were successfully detected, the metastatic status of SLNs was correctly diagnosed with SMI.

Conclusions and significance: Although more clinical data are needed based on a larger cohort, establishing the CEUS-guided SLN-detection and criteria for the accurate diagnosis of SLN-metastases using SMI would be valuable as an alternative to radioisotope method, in oral and oropharyngeal cancers.

Chinese abstract

背景：对于头颈部肿瘤前哨淋巴结（SLN）活检, 放射性同位素法一直为金标准。但是, 该方法存在着一些问题, 如：不可避免的辐射照射、必要的昂贵设备。

目的：为了克服这些问题, 我们评估了造影增强超声扫描术（CEUS）所引导的前哨淋巴结（SLN）检测方法, 并利用新的超声技术、超显微血管成像（SMI）来预测SLN的转移状态。

方法：本研究的对象是10例无颈淋巴结转移的患者（口腔癌6例, 口咽癌4例）。将超声造影剂Sonazoid™渗透到主要部位的粘膜中, 观察颈部淋巴管和SLN。检测到的SLNs用SMI进行血液流动检测, 以区分SLNs的转移是阳性还是阴性。

结果：10例患者中8例成功检测到SLN。在这8例成功检测到SLN的患者中, 有7例通过SMI正确诊断 出SLN的转移状态。

结论和意义：虽然还需要更多的以更大的研究对象群为基础的临床数据, 但是建立CEUS引导的SLN检测和标准, 使用SMI 准确诊断SLN转移, 对于治疗口腔癌和口咽癌, 将是一个有价值的可以替代放射性同位素法的方法。

Keywords:

• Contrast-enhanced ultrasonography
• oral cancer
• oropharyngeal cancer
• sentinel lymph node
• Sonazoid™
• superb microvascular imaging

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by a grant-in-aid from The Public Trust Fund For Clinical Cancer Research