气管壁镜面伪像对甲状腺结节微波消融治疗的不利影响

目的 探讨甲状腺结节微波消融围手术期气管壁镜面伪像对消融术的不利影响及其成因。方法 对2018年1月至2018年10月在上海国际医学中心接受甲状腺结节微波消融治疗的304例患者的围手术期超声影像资料进行系统性研究。就出现气管壁镜面伪像的病例数、伪像来源、伪像特点，以及伪像对消融术的影响进行总结。分析发生气管壁镜面反射伪像的影响因素。结果 消融术前、术中、术后各期超声影像中共169（55.59%）例出现气管壁镜面反射伪像，包括甲状腺结节伪像20例（11.83%）、隔离液注射针伪像133例（78.70%）、微波消融针伪像16例（9.47%）、液体隔离带伪像137例（81.07%）、甲状腺消融区伪像8例（4.73%）。各期中，以消融术中出现伪像者最多，达88.17%（149/169）。结论 气管壁镜面反射引起的镜面伪像在甲状腺结节微波消融围手术期具有较高的发生率，结节位置邻近气管、气管壁扁平化、平坦界面线度大于结节实像是形成气管壁镜面反射伪像的主要因素。结节、消融区、液体隔离带的直接压迫是气管壁扁平化的直接原因。

Adverse effect of mirror artifact across trachea on microwave ablation of thyroid nodules

Objective To study the adverse effect of mirror artifacts generated from the specular reflection of trachea wall on microwave ablation (MWA) treatment of thyroid nodules and the causes. Methods Perioperative ultrasound imaging data of 304 patients who received MWA of thyroid nodules in Shanghai International Medical Center from Jan. 2018 to Oct. 2018 were systemically studied. The occurrence rate, sources, acoustic characteristics of the mirror artifacts and the adverse effects of mirror artifacts on MWA were summarized. The factors contributing to specular reflection of trachea were analyzed. Results A total of 169 cases (55.59%) presented tracheal mirror reflection artifacts in this study. The sources of mirror artifacts included thyroid nodules (20 cases, 11.83%), injection needle (133 cases, 78.70%), ablation electrode (16 cases, 9.47%), hydro-dissection zone (137 cases, 81.07%), and remote ablated area of thyroid nodule (8 cases, 4.73%). We also found that 88.17% (149/169) of mirror artifacts were during the MWA operative period. Conclusion Mirror artifacts generated from the specular reflection of trachea wall are commonly seen in the perioperative period of thyroid nodule MWA. Lesion close to the trachea, flattened tracheal wall, and flat interface linearity larger than the real source dimension are the important causes of mirror artifacts. Direct compression on the tracheal wall caused by thyroid nodules, ablated areas and hydro-dissection zone are the main causes of flattened tracheal wall.