Grani Giorgio, D'Alessandri Mimma, Carbotta Giovanni, Nesca Angela, Del Sordo Marianna, Alessandrini Stefania, Coccaro Carmela, Rendina Roberta, Bianchini Marta, Prinzi Natalie, Fumarola Angela
From the Department Of Experimental Medicine, Unit of Endocrinology, "Sapienza" Università di Roma, Rome, Italy.
Medicine (Baltimore). 2015 Jul;94(27):e1129. doi: 10.1097/MD.0000000000001129.
Ultrasonography is the main imaging method for the workup of thyroid nodules. However, interobserver agreement reported for echogenicity and echotexture is quite low. The aim of this study was to perform quantitative measurements of the degree of echogenicity and heterogeneity of thyroid nodules, to develop an objective and reproducible method to stratify these features to predict malignancy.A retrospective study of patients undergoing ultrasonography-guided fine-needle aspiration was performed in an University hospital thyroid center. From January 2010 to October 2012, 839 consecutive patients (908 nodules) underwent US-guided fine-needle aspiration. In a single ultrasound image, 3 regions of interest (ROIs) were drawn: the first including the nodule; the second including a portion of the adjacent thyroid parenchyma; the third, the strap muscle. Histogram analysis was performed, expressing the median, mean, and SD of the gray levels of the pixels comprising each region. Echogenicity was expressed as a ratio: the nodule/parenchyma, the nodule/muscle, and parenchyma/muscle median gray ratios were calculated. The heterogeneity index (HI) was calculated as the coefficient of variation of gray histogram for each of the 3 ROIs. Cytology and histology reports were recorded.Nodule/parenchyma median gray ratio was significantly lower (more hypoechoic) in nodules found to be malignant (0.45 vs 0.61; P = 0.002) and can be used as a continuous measure of hypoechogenicity (odds ratio [OR] 0.12; 95% confidence interval [CI] 0.03-0.49). Using a cutoff derived from ROC curve analysis (<0.46), it showed a substantial inter-rater agreement (k = 0.74), sensitivity of 56.7% (95% CI 37.4-74.5%), specificity of 72.0% (67.8-75.9%), positive likelihood ratio (LR) of 2.023 (1.434-2.852), and negative LR of 0.602 (0.398-0.910) in predicting malignancy (diagnostic odds ratio 3.36; 1.59-7.10). Parenchymal HI was associated with anti-thyroperoxidase positivity (OR 19.69; 3.69-105.23). The nodule HI was significantly higher in malignant nodules (0.73 vs 0.63; P = 0.03) and, if above the 0.60 cutoff, showed sensitivity of 76.7% (57.7-90.1%), specificity of 46.8% (42.3-51.4%), positive LR of 1.442 (1.164-1.786), and negative LR of 0.498 (0.259-0.960).Evaluation of nodule echogenicity and echotexture according to a numerical estimate (nodule/parenchyma median gray ratio and nodule HI) allows for an objective stratification of nodule echogenicity and internal structure.
超声检查是甲状腺结节检查的主要影像学方法。然而，据报道，不同观察者对回声性和回声纹理的一致性相当低。本研究的目的是对甲状腺结节的回声性程度和异质性进行定量测量，开发一种客观且可重复的方法对这些特征进行分层以预测恶性肿瘤。在一家大学医院的甲状腺中心对接受超声引导下细针穿刺的患者进行了一项回顾性研究。2010年1月至2012年10月，连续839例患者（908个结节）接受了超声引导下细针穿刺。在单幅超声图像中，绘制3个感兴趣区域（ROI）：第一个包括结节；第二个包括部分相邻甲状腺实质；第三个是带状肌。进行直方图分析，得出构成每个区域的像素灰度值的中位数、均值和标准差。回声性用比率表示：计算结节/实质、结节/肌肉以及实质/肌肉的中位数灰度比。异质性指数（HI）计算为3个ROI中每个区域灰度直方图的变异系数。记录细胞学和组织学报告。在被发现为恶性的结节中，结节/实质中位数灰度比显著更低（更低回声）（0.45对0.61；P = 0.002），并且可作为低回声性的连续测量指标（优势比[OR] 0.12；95%置信区间[CI] 0.03 - 0.49）。使用从ROC曲线分析得出的临界值（<0.46），其在预测恶性肿瘤方面显示出较高的观察者间一致性（k = 0.74），敏感性为56.7%（95% CI 37.4 - 74.5%），特异性为72.0%（67.8 - 75.9%），阳性似然比（LR）为2.023（1.434 - 2.852），阴性LR为0.602（0.398 - 0.910）（诊断优势比3.36；1.59 - 7.10）。实质HI与抗甲状腺过氧化物酶阳性相关（OR 19.69；3.69 - 105.23）。恶性结节中的结节HI显著更高（0.73对0.63；P = 0.03），并且如果高于0.60的临界值，显示敏感性为76.7%（57.7 - 90.1%），特异性为46.8%（42.3 - 51.4%），阳性LR为1.442（1.164 - 1.786），阴性LR为0.498（0.259 - 0.960）。根据数值估计（结节/实质中位数灰度比和结节HI）对结节回声性和回声纹理进行评估，能够对结节回声性和内部结构进行客观分层。
