气道内超声弹性技术对肺癌患者肺门纵膈淋巴结转移的诊断价值

Value of endobronchial ultrasound elastography in the diagnosis of mediastinal and hilar lymph node metastasis in lung cancer

目的:探讨气道内超声弹性成像技术对肺癌患者肺门纵膈淋巴结转移的诊断价值。方法:选取拟手术治疗的肺癌患者40例,术前予以超声支气管镜检查、淋巴结支气管内超声及弹性成像检查,并予以支气管内超声引导下的经支气管针吸活检术。通过比较良恶性淋巴结的超声弹性成像特征及弹性成像评分法与常规超声影像学特征诊断恶性淋巴结准确性差异,评估气道内超声弹性成像技术鉴别淋巴结良恶性的价值。结果:1)常规超声影像学特征中鉴别良恶性淋巴结差异有统计学意义的指标包括低回声、回声不均、边界清楚、短径大于1 cm(均P<0.01);2)气道内超声弹性成像评分在良恶性淋巴结中差异有统计学意义(P<0.01);3)弹性评分法对良恶性淋巴结的鉴别明显优于常规超声图像特征中的任何一种。弹性评分≥2.5分诊断恶性淋巴结的曲线下面积(area under the curve,AUC)最大,其诊断恶性淋巴结的特异度、敏感度、阳性预测值及阴性预测值分别为76.9%,85.7%,85.7%及76.9%,诊断的准确率为82.3%。联合指标中以弹性评分联合低回声、边缘清晰、直径大于1 cm诊断价值最大,AUC为0.911,诊断恶性淋巴结的特异度、敏感度、阳性预测值及阴性预测值分别为84.6%,88.1%,90.2%及81.5%,诊断的准确率为86.8%。结论:超声支气管镜下弹性成像技术能有效实现对肺癌患者肺门纵膈淋巴结良恶性的鉴别,比传统的淋巴结支气管内超声的图像准确率高。弹性评分联合常规超声图像特征能提高诊断效率。

Objective： To assess the value of endobronchial ultrasound elastography in the diagnosis of mediastinal and hilar lymph node metastasis in lung cancer. Methods： A total of 40 patients with lung cancer underwent ultrasonic bronchoscope examination before operation. Elastography and standard endobronchial ultrasound （EBUS） of lymph nodes were performed before EBUS-guided transbronchial needle aspiration （EBUS-TBNA）. The elastography characteristics was compared between benign and malignant lymph nodes. The diagnosis accuracy in malignant lymph nodes was also compared between the elastography and the standard EBUS. The value of the elastography was assessed in distinguishing the benign and malignant lymph nodes. Results： 1） The significant indicators of standard EBUS in diagnosis of malignant lymph nodes were hypoechonic nodes, uneven echo, distinct boundary and short diameter greater than 1 cm （all P〈0.01）. 2） There was significant difference in the elastosonography grading score between benign and malignant lymph nodes （P〈0.01）. 3） The elastography grading score was more sensitive and specific in determining the malignant lymph node than the standard EBUS criteria. The area under the receiver operating characteristic curve （AUC） was maximal when the elastography grading score was ≥2.5. The specificity, sensitivity, positive predictive value, negative predictive value of elastography grading score was 76.9%, 85.7%, 85.7% and 76.9% in distinguishing malignant and benign nodes. The overall accuracy of elastography grading score was 82.3%. The combination of elastography grading score, low echo, distinct boundary and short diameter greater than 1 cm showed the best diagnostic efficiency value. The AUC was 0.911. In distinguishing malignant and benign nodes, the specificity, sensitivity, positive predictive value, negative predictive value and accuracy of the combined indexes was 84.6%, 88.1%, 90.2%, and 81.5% respectively. The overall accuracy was 86.8%. Conclusion： The endobronchial ultrasound elastography can effectively distinguish the mediastinal and hilar lymph node metastasis in lung cancer. The diagnosis accuracy of elastography in malignant lymph node is higher than that of standard EBUS criteria. The combination of elastosonography grading score and standard EBUS criteria can improve the diagnostic efficiency.