甲狀腺结节论文磁共振弥散加权成像在鉴别甲状腺良恶性结节中的价值.docVIP

甲状腺结节论文：磁共振弥散加权成像在鉴别甲状腺良恶性结节中的价值 【中文摘要】探讨磁共振(MRI)弥散加权成像(DWI)在鉴别甲状腺良恶性结节中的价值。方法：采用平面回波成像(EPI)技术,对50例甲状腺结节患者(良性组41例,恶性组9例)和20名健康志愿者行DWI检查,分别测量b值取200、400、600s/mm2时良恶性结节和甲状腺结节患者及健康志愿者正常甲状腺的表观弥散系数(ADC)值,比较其差异,并计算以恶性组ADC值95%可信区间的上限值作为良恶性结节的分界值时的诊断效能。所有患者均经手术病理证实。结果：b值为200、400、600s/mm2时良性组与恶性组之间ADC值的差异均有统计学意义(P0.05)。将恶性组ADC值95%可信区间的上限值作为良恶性结节鉴别的分界值,则b值为200、400、600 s/mm2时,分界值分别为2.149×10-3、1.386×10-3、1.055×10-3mm2/s。应用ROC曲线分析不同b值时ADC分界值诊断恶性结节的效能,显示b值为400s/mm2时价值最大,其敏感性、特异性、准确度、阳性预测值及阴性预测值分别为92.59%、71.43%、88.24%、93.10%及71.43%。结论：甲状腺恶性结节的ADC值低于良性结节,差异有统计学意义,b值400s/mm2时,ADC值以1.386×10-3mm-2/s为鉴别良恶性结节的分界值有较高的准确度。 【英文摘要】:To investigate the value of MR diffusion weighted imaging(DWI) in differentiating malignant from benign thyroid lesions.Material and methods:DWI studies using spinecho echo planner imaging(EPI) sequence with a b value of 200,400 and 600s/mm respectively.as well as routine MRI were performed in 50 patients with pathology proved focal thyroid lesions(benign,n=41;malignant,n=9)and 20 healthy subjects.The apparent diffusion coefficient(ADC) values were measured and their differences were compared.Taking upper limits of 95% confidence interval of mean ADC values as the diagnostic threshold to differentiate malignant from benign lesions to analyze the ADC value in the diagnosis of malignant lesions with different b values.Results:The mean ADC values of thyroid benign and malignant lesions showed statistic differences with a b value of 200,400,600s/mm2 respectively(P 0.05).Taking upper limits of 95% confidence interval of mean ADC values as the diagnostic threshold to differentiate malignant from benign lesions,the diagnostic threshold was 2.149×10-3、1.386×10-3、1.055×10-3mm2/s with b values of 200,400 and 600s/mm2 respectively.Using receiver operating characteristic curve(ROC) to analyze the ADC value in the diagnosis of malignant lesions with different b values,the most optimal b value was 400s/mm2.The sensitivity,specificity,accuracy,positive predicative value and ne