MD, PhD, Unit of Internal Medicine and Endocrinology, Fondazione Salvatore Maugeri Istituto di Ricovero e Cura a Carattere Scientifico, via S. Maugeri 10, 27100 Pavia, Italy.
J Clin Endocrinol Metab. 2013 Dec;98(12):4790-7. doi: 10.1210/jc.2013-2672. Epub 2013 Sep 24.
Ultrasound (US) elastography (USE) was recently been reported as a sensitive, noninvasive tool for identifying thyroid cancer. However, the accuracy of this technique is hampered by the intra- and interoperator variability, some US features of the nodule, and the coexistence of autoimmune thyroid disease (ATD).
The purpose of this article was to assess the accuracy of USE findings in the differential diagnosis of thyroid nodules compared with other US features to evaluate its feasibility in the presence of ATDs and identify the strain index (SI) cutoff with the highest diagnostic performance.
We evaluated 528 consecutive patients for a total of 661 thyroid nodules. All nodules underwent fine-needle aspiration cytology (FNAC) and USE evaluation. The SI was calculated as a ratio of the nodule strain divided by the strain of the softest part of the surrounding normal tissue.
The median SI value was significantly higher in THY4 and THY5 than in THY2 nodules in ATD-positive, ATD-negative, and ATD-unknown patients. The cutoff of SI for malignancy was estimated to be 2.905 by receiver operating characteristic curve analysis in a screening set (379 FNAC results), and then tested in a replication set (252 FNAC results). In all cases, a SI value of ≥ 2.905 conferred to the nodule a significantly greater probability of being malignant. This SI cutoff had the greatest area under the curve, sensitivity, and negative predictive value, compared with the conventional US features of malignancy.
The elastographic SI has a high sensitivity, specificity, and negative predictive value for the diagnosis of thyroid malignancy both in the presence and in the absence of ATD. If our data on USE are also confirmed in THY3 nodules, FNAC could be avoided in a number of thyroid nodules with certain features.
超声弹性成像（USE）最近被报道为一种敏感、无创的工具，可用于识别甲状腺癌。然而，该技术的准确性受到操作者间和操作者内的可变性、结节的某些超声特征以及自身免疫性甲状腺疾病（ATD）的共存的影响。
本文旨在评估 USE 结果在甲状腺结节鉴别诊断中的准确性，并与其他超声特征进行比较，以评估其在 ATD 存在时的可行性，并确定具有最高诊断性能的应变指数（SI）截断值。
我们对 528 例连续患者的 661 个甲状腺结节进行了评估。所有结节均进行了细针抽吸细胞学检查（FNAC）和 USE 评估。SI 计算为结节应变与周围正常组织最软部分应变的比值。
在 ATD 阳性、ATD 阴性和 ATD 未知患者中，THY4 和 THY5 结节的中位 SI 值明显高于 THY2 结节。通过接受者操作特征曲线分析，在筛查组（379 例 FNAC 结果）中估计了用于恶性肿瘤的 SI 截断值为 2.905，然后在验证组（252 例 FNAC 结果）中进行了测试。在所有情况下，SI 值≥2.905的结节恶性可能性显著增加。与恶性肿瘤的常规超声特征相比，该 SI 截断值具有最大的曲线下面积、敏感性和阴性预测值。
在存在和不存在 ATD 的情况下，弹性成像 SI 对甲状腺恶性肿瘤的诊断具有较高的敏感性、特异性和阴性预测值。如果我们在 THY3 结节上的 USE 数据也得到证实，那么在具有某些特征的许多甲状腺结节中可以避免 FNAC。
