超声影像特点对甲状腺结节性质的诊断价值

目的 总结甲状腺良、恶性结节的超声影像特点,探讨其术前对甲状腺结节性质的诊断价值.方法 回顾性分析2000年1月至2008年7月因触诊或超声检查发现甲状腺结节并在解放军总医院进行手术的患者1501例,记录术前超声检查的结节的二维声像(结节数目、大小、声像结构、同声类型、形态、边缘、有无钙化及钙化类型)、内部及周边血流和颈部淋巴结异常肿大等资料,根据术后病理诊断将所有结节分为2组:良性组1864个结节和恶性组259个结节.结果 (1)多结节组单个结节恶性率低于单结节组[10.2%(150/1470)比16.7%(109/653),P=0.000];良性结节的平均最大直径大于癌性结节[(2.4±1.4)cm比(2.1±1.9)cm,P=0.009].(2)细小点状钙化、形态不规整、边界不清、实性和低回声等声像特征在癌性结节中更为常见;形态不规整对癌性结节诊断敏感性和阳性预测值最高,而细小点状钙化诊断准确性最高.(3)结节内血流分布模式中以血流丰富者发生癌变几率最高,周边血流的多少不能反映结节的性质;伴同侧颈部淋巴结异常肿大的结节癌变率高于不伴异常肿大者[28.3%(80/283)比9.6%(92/963),P＜0.01].(4)如果将细小点状钙化、形态不规整、边缘不清、实性、低回声伴同侧颈淋巴结异常肿大视为癌性结节征象,上二述征象越多,癌变可能性越大.结论 尽管癌性结节没有特异性超声影像特点,微钙化和形态不规整与癌性病变关系更密切,综合分析所有影像特点可进一步提高超声对甲状腺结节性质的鉴别价值.

Predictive value of sonographic features in preoperative evaluation of malignant thyroid nodules

Objective To retrospectively evaluate the diagnostic accuracy of ultrasonographic (US)features for the pre-operative differentiation of benign and malignant thyroid nodules by using pathological diagnosis as the reference standard. Methods A total of 1501 patients with 2123 thyroid nodules ( 1864 malignant, 259 benign ) diagnosed intra-operatively and undergoing pre-operative ultrasonography at our hospital were recruited. The following characteristics of US images were evaluated: nodule size, shape,margin, echotexture, echogenicity, presence and type of calcification, blood flow inside or around nodules and the presence of ipsilateral cervical lymphadenectasis. Results ( 1 )The risk of malignancy was higher in a solitary nodule than in a non-solitary nodule [16.7% (109/653) vs 10.2% (150/1470), P = 0.000].The mean diameter of benign nodules was larger than that of malignant nodules [( 2.4 ± 1.4 ) vs ( 2.1 ±1.9) cm, P = 0.009]. (2) Microcalcification, irregular shape, ill-defined border, solid and hypoechogenicity were more common in malignant nodules. Irregular shape had the highest sensitivity and positive predictive value while microcalcification had the highest diagnostic accuracy. (3) Nodules with a rich blood flow inside tended to have a higher risk of malignancy. The distribution pattern of blood flow around the nodules was not associated with the differentiation of benign and malignant thyroid nodules.Nodules with the presence of ipsilateral cervical lymphadenectasis had a higher risk of malignancy than those without lymphadenectasis [28.3% ( 80/283 ) vs 9.6% (92/963), P ＜ 0.01]. (4) If microcalcification,irregular shape, ill-defined border, solid, hypoechogenicity and the presence of ipsilateral cervical lymphadenectasis were treated as the characteristics of malignancy, a higher frequency of these characteristics was correlated with a higher risk of malignancy. Conclusion Despite a lack of specific US imaging characteristics in malignant thyroid nodules, microcalcification and irregular shape appear closely correlated with malignancy. A combined use of conventional US characteristics may improve the accuracy of differential diagnosis.