超声弹性应变比对甲状腺结节诊断一致性的研究

Evaluation of inter-observers consistencyin differentiating diagnosis of thyroid nodules based on calculation of the strain ratio on thyroid sonoelastography

目的探讨三位超声医师应用超声弹性应变比（strainratio，sR）诊断甲状腺良恶性结节的一致性。方法三位超声医师分别对经病理证实的68例82个甲状腺结节（恶性49个，良性33个）进行常规超声检查及SR测定，根据5分法行常规超声及联合SR诊断评分，并构建ROc曲线。结果联合SR后三位医师诊断3分的结节数目（性质待定）明显少于常规超声，1分及5分者明显增多。诊断一致性检验结果显示，常规超声诊断两两间kappa值分别为0．441、0．536及0．517，联合SR后两两间kappa值分别为0．715、0．734及0．803（P〈0．05），医师间诊断一致性明显提高。三位医师联合SR诊断的敏感性、准确性、阳性预测值范围分别为89．80,4～93．9％、82．9％～84．1％及82．1％～84．6％，高于单独超声诊断的63．3％～65．3％、54．9oA～62．20,4及61．5％～66．0％，差异有统计学意义（P〈0．05）；联合SR与单独超声诊断ROC曲线下面积分别为0．929对0．835、0．938对0．852、0．917对0．840，差异均有统计学意义（P〈0．05）。结论联合SR有助于提高甲状腺结节良恶性的诊断率，且提高不同医师间诊断一致性。

Objective To investigate inter-observers consistencyin differentiating benign or malignant thyroid nodules by calculating strain ratio （SR）. Methods Eighty-two thyroid nodules in 68 patients were examined with conventional ultrasound （US） and real-time elastography by three independent ultrasound doctors. SR of the nodule and the surrounding tissue was calculated. A 5-point confidence level was used to discriminate malignant from benign nodules by US and then by combined with SR. The diagnostic performances were evaluated by receiver operating characteristic （ROC） analysis. Results With combination of US and SR, the numbers of lesions with 3-point were less than US alone in all three doctors, while the numbers of 1-point and 5-point were increased apparently. A better inter-observers consistency was achieved in combination of SR and US, compared to US alone （ k = 0. 715,0. 734,0. 803 versus 0.441, 0. 536,0. 517, all P ~0.05）. The sensitivity, positive predictive value, and accuracy in three operators increased significantly when combined with SR （all P ~ 0.05 ）. ROC analysis revealed significant improvement in differential diagnosis between malignant and benign thyroid nodules with combination US and SR. The areas under the ROC curve were 0. 929 at combined with SR and 0. 835 at US for doctor 1, 0. 938 and 0. 852 for doctor 2, and 0. 917 and 0. 840 for doctor 3 （ P d0.05, respectively）. Conclusions As a novel semi-quantitative method, combination with the SR could help to improve differential diagnosis between benign or malignant thyroid nodules and was showed reliable interoperator consistency.