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.doc

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2.14910-3、1.38610-3、1.05510-3mm2/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1.38610-3mm-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 2.14910-3、1.38610-3、1.05510-3mm2/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 negative predicative value were 92.59%、71.43%、88.24%、93.10% and 71.43%,respectively.Conclusions:The mean ADC value of thyroid malignant lesions was lower than that of benign lesions,and ADC value is valuable in differentiating malignant from benign thyroid lesions with a threshold of 1.38610-3 mm2/s and a b value of 400 s/mm2.【关键词】甲状腺结节 磁共振成像 弥散加权成像【英文关键词】thyroid nodule MRI DWI【目录】磁共振弥散加权成像在鉴别甲状腺良恶性结节中的价值摘要3-4ABSTRACT4第1章 引言8-10第2章 材料与方法10-142.1 研究对象与临床资料102.2 磁共振检查方法10-122.2.1 硬件设备10-112.2.2 检查前准备112.2.3 磁共振平扫112.2.4 DWI扫描112.2.5 测量ADC值11-122.2.6 数据处理122.3 图像分析122.3.1 磁共振平扫图像分析122.3.2 DWI、ADC图像分析122.4 统计学处理12-14第3章 结果14-213.1 正常甲状腺的磁共振图像表现143.2 甲状腺良、恶性结节组的磁共振平扫表现14-153.3 甲状腺良、恶性结节组在磁共振平扫图像上信号强度的比较153.4 磁共振平扫鉴别甲状腺良、恶性结节的价值153.5 甲状腺良、恶性结节组的DWI及ADC图表现15-163.6 不同b值时甲状腺良、恶性结节组ADC值的比较16-183.7 ADC值鉴别甲状腺良、恶性结节的价值18-203.8 不同b值时甲状腺良性结节组、恶性结节组及健康对照组正常甲状腺区的ADC值的比较20-21第4章 讨论21-304.1 磁共振平扫鉴别甲状腺良、恶性结节的价值21-234.1.1 结节的信号强度214.1.2 结节的形状及边界214.1.3 结节邻近组织结构受累情况21-224.1.4 颈部淋巴结的情况22-234.2 DWI的原理234.3 影响DWI的因素及其相关参数的选择23-264.3.1 DWI上组织信号衰减的影响因素23-244.3.2 b值对DWI的影响及其选择244.3.3 扩散系数和表观扩散系数及其影响因素24-254.3.4 T2透射效应25-264.4 头颈部应用DWI的可行性26-274.5 DWI及ADC值鉴