多参数MRI对甲状腺腺瘤和甲状腺乳头状癌的鉴别诊断价值

Multiparametric MR Imaging for Differentiating between Thyroid Adenoma and Papillary Thyroid Carcinoma

目的探讨多参数磁共振成像表观扩散系数(ADC)和时间信号强度曲线(TIC)在甲状腺腺瘤(TA)和甲状腺乳头状癌(PTC)诊断及鉴别诊断中的价值。方法回顾性分析2016年1月至2017年6月江苏大学附属人民医院收治的88例患者共计132枚病灶的影像学资料,经病理证实TA 53枚和PTC 79枚,依次行磁共振平扫、扩散加权成像(DWI)、动态增强磁共振成像(DCE-MRI),计算多b值时TA、PTC的ADC值,绘制受试者工作特征(ROC)曲线,判定诊断阈值并评价诊断效能,绘制病变的TIC,最后DWI联合DCE-MRI对TA、PTC进行鉴别诊断,与病理对照,研究DWI和DCE-MRI联合应用鉴别诊断TA和PTC的敏感度、特异度、准确度、阳性预测值、阴性预测值。结果 b=500 s/mm^2时,DWI诊断PTC的ADC值诊断效果最佳,ROC曲线下面积(AUC)为0.871,诊断阈值取1.538×10^(-3)mm^2/s时,诊断PTC的敏感度为83.0%、特异度为78.5%、准确度为81.8%、阳性预测值为78.2%、阴性预测值为84.3%,约登指数为61.5;DCE-MRI中,PTC 62枚为Ⅲ型曲线,TA 40枚为Ⅰ型曲线,差异具有统计学意义(P=0.000),DCE-MRI的TIC曲线诊断PTC的敏感度为78.5%、特异度为75.5%、准确度为77.3%、阳性预测值为82.7%、阴性预测值为70.2%;b=500 s/mm^2时,DWI和DCE-MRI联合诊断PTC的敏感度为91.1%、特异度为90.6%、准确度为90.9%、阳性预测值为93.5%、阴性预测值为87.3%;DWI、DCE-MRI、DWI和DCE-MRI联合诊断,三者相比较其敏感性、特异性、准确性、阴性预测值、阳性预测值差异均具有统计学意义(P=0.044、0.010、0.024、0.009、0.006)。结论多参数MRI鉴别诊断TA和PTC较单一DCE-MRI或DWI诊断效能强。

Objective To evaluate multiparametric MR imaging with combined use of apparent diffusion coefficients(ADCs)and time-signal intensity curves(TIC)for discriminating papillary thyroid carcinoma from thyroid adenoma.Methods From January 2016 to June 2017,88 consecutive patients(total of 132 lesions)underwent surgery for pathologically confirmed 53 thyroid adenoma and 79 papillary thyroid carcinoma in Jiangsu university affiliated people,s hospital,then non-contrast enhanced MR imaging(NCE-MRI),MR diffusion-weighted imaging(MR-DWI)and contrast-enhanced MR imaging(DCE-MRI)scan was performed,the apparent diffusion coefficient(ADC)values of thyroid adenoma and papillary thyroid carcinoma at different b values of DWI were calculated,receiver operating characteristic(ROC)curves were drawn and were used to evaluate the diagnostic value of ADC values in thyroid adenoma and papillary thyroid carcinoma,then subsequently attain the TICs.Thyroid adenoma and papillary thyroid carcinoma were examined by combined application of MR-DWI and DCE-MRI,and the results were compared with those of pathological analysis with the sensitivity,specificity,positive predictive value,negative predictive value and accuracy.Results The highest diagnostic accuracy can be obtained with b-value of 500 s/mm2 with the area under curve 0.871.When the b-value was selected as 500 s/mm2 and the diagnostic threshold was 1.538×10-3mm2/s according to the ROC curve,the sensitivity,specificity,accuracy,positive predictive value and negative predictive were 83.0%,78.5%,81.8%,78.2%,84.3%,Youden index 61.5.For DCE-MRI,62 papillary thyroid carcinoma showedⅢcurve,40 thyroid adenoma showedⅠcurve,with statistically significant difference(P=0.000),for DCE-MRI,the sensitivity,specificity,accuracy,positive predictive value and negative predictive values were 78.5%,75.5%,77.3%,82.7%,70.2%.For combined application of DWI and DCE-MRI,the sensitivity,specificity,accuracy,positive predictive value and negative predictive value were 91.1%,90.6%,90.9%,93.5%,87.3%;the sensitivity,specificity,accuracy positive predictive value and negative predictive value,demonstrated a statistically significant difference(P=0.044,0.010,0.024,0.009,0.006).Conclusion Multiparametric MR imaging has more diagnostic validity than other diagnotic examinations to identify thyroid adenoma and papillary thyroid carcinoma.