扩散加权成像在甲状腺腺瘤和乳头状癌鉴别诊断中的价值

Efficacy of Diffusion-Weighted MR Imaging in Differentiating Papillary Thyroid Carcinoma from Follicular Thyroid Adenoma

目的探讨MRI扩散加权成像(DWI)在滤泡性甲状腺腺瘤(FTA)和乳头状癌(PTC)鉴别诊断中的价值。方法回顾性分析58例患者经手术病理证实的65枚甲状腺结节(其中FTA 26枚,PTC 39枚)的不同b值DWI扫描生成的表观扩散系数(ADC)图像,测量肿瘤实性部分的ADC值,对FTA和PTC组的ADC值进行独立样本t检验,绘制受试者工作特征(ROC)曲线评价其诊断效能。结果FTA组肿瘤的不同b值ADC值均明显高于PTC组肿瘤,两组肿瘤的ADC值差异具有统计学意义(P<0.05)。b值取300 s/mm2时,FTA、PTC的ADC值分别为(2.565±0.504)×10-3mm2/s、(1.707±0.462)×10-3mm2/s;b值取500 s/mm2时,FTA、PTC的ADC值分别为(2.266±0.486)×10-3mm2/s、(1.434±0.406)×10-3mm2/s;b值取800 s/mm2时,FTA、PTC的ADC值分别为(1.907±0.489)×10-3mm2/s、(1.204±0.376)×10-3mm2/s。其中b值取500 s/mm2时,ADC值对FTA和PTC的鉴别诊断效果最佳;ROC曲线下面积(AUC)为0.905;诊断阈值取1.795×10-3mm2/s时,诊断的敏感度、特异度、阳性预测值、阴性预测值分别为87.18%、84.62%、89.5%及81.5%。结论不同b值时ADC值均有助于FTA和PTC的鉴别诊断,其中b值取500 s/mm2时ADC对FTA和PTC的诊断效能最佳。

Objective To assess the utility of diffusion weighted imaging(DWI)in differentiating papillary thyroid carcinoma(PTC)from follicular thyroid adenoma(FTA).Methods Fifty-eight patients with single or multiple thyroid nodules(65 nodules in total,39 PTCs and 26 FTAs)were included in this study.The thyroid tumors’apparent diffusion coefficient(ADC)with different b values was assessed by Independent-Sample t test.Receiver operator characteristic(ROC)curves were drawn and used to evaluate the diagnostic efficiency of ADC in distinguishing PTC from FTA.Results FTAs showed significantly higher ADC values than PTCs.The b-300 s/mm2 ADC values of FTA and PTC were(2.565±0.504)×10-3mm2/s and(1.707±0.462)×10-3mm2/s respectively,whereas the b-500 s/mm2 ADC values were(2.266±0.486)×10-3mm2/s and(1.434±0.406)×10-3mm2/s respectively.The highest diagnostic efficiency can be obtained with b-500 s/mm2,the area under the ROC curve was 0.905;the diagnostic threshold was set as 1.795×10-3mm2/s,the sensitivity,specificity,positive predictive value and negative predictive values were 87.18%,84.62%,89.5%and 81.5%,respectively.Conclusion The ADC values are helpful in differentiating PTC from FTA,and the best result can be obtained by using b-value of 500 s/mm2.