3.0 T磁共振T2WI联合高b值DWI对甲状腺微小乳头状癌的诊断价值

The Diagnostic Value of 3.0 T Magnetic Resonance TWI Combined with High b-value DWI for Papillary Thyroid Microcarcinoma

目的建立一种多参数甲状腺磁共振成像(MRI)检查与诊断方式,探讨T2WI联合高b值扩散加权成像(DWI)对甲状腺良、恶性微小结节的诊断价值。方法搜集拟行手术的甲状腺微小结节患者65例,术前均常规进行MRI检查,将其分为良性组和恶性组,以病理结果为金标准,通过测量结节平均信号强度与椎旁肌的平均信号强度来分别计算每个甲状腺结节的T1、T2信号强度比(SIRT1、SIRT2),测量结节的表观扩散系数(ADC)值(b=0、2000 s/mm2),比较分析两组患者SIR和ADC值,绘制受试者工作特征曲线(ROC)评价其诊断效能。结果恶性组SIRT2(P=0.001)和ADC(P=0.001)明显低于良性组;SIRT2诊断恶性微小结节(微小乳头状癌)的灵敏度88.9%,特异度82.7%,阳性预测值86.5%、阴性预测值86.7%,ROC曲线下面积(AUC)为0.825;ADC诊断恶性微小结节(微小乳头状癌)的灵敏度94.4%,特异度89.7%,阳性预测值91.9%、阴性预测值92.8%,AUC为0.867;SIRT2和ADC联合诊断的灵敏度,特异度和AUC分别为94.4%,93.1%和0.882。结论MRI多参数(T2WI联合DWI)对甲状腺微小结节良、恶性鉴别具有重要价值。

Objective To establish a multi-parameter thyroid magnetic resonance imaging(MRI)examination and diagnosis method,and to analyze the specificity and sensitivity of T2-weighted imaging(T2WI)combined with diffusion-weighted imaging(DWI)in the diagnosis of benign and malignant thyroid micro-nodules.Methods Sixty-five patients with thyroid micro-nodules(65 nodules)were enrolled in this study and divided into benign micro-nodule group and malignant micro-nodule group according to the results of pathological examination.The signal intensity ratios of T1 and T2(SIR,T1,T2)of each thyroid micro-nodule were calculated by measuring the average signal intensity of micro-nodule and paravertebral muscle respectively,and the apparent diffusion coefficient(ADC)value(b=0,2000 s/mm2)of micro-nodules was measured.The SIR and ADC values of the two groups were compared and analyzed.Receiver operating characteristic curve(ROC)was drawn to evaluate the diagnostic efficacy.Results The sensitivity,specificity,positive predictive value and negative predictive value of T2 SIR in malignant micro-nodule group(papillary thyroid microcarcinoma)were 0.889,0.827,0.865,0.867 and 0.825 respectively.The sensitivity,specificity,positive predictive value and negative predictive value of ADC in diagnosis of papillary cancer were 0.944,0.897,0.919,0.928 and 0.825 respectively.The area under the curve(AUC)was 0.867;the sensitivity,specificity and area under the ROC curve and T2 SIR were 94.4%,93.1%and 0.882,respectively.Conclusion Multiparameter MR imaging(T2 WI combined with DWI)has important value in differentiating benign from malignant thyroid micro-nodules.