摘要
目的:探讨MR扩散加权成像在甲状腺良恶性病变鉴别诊断中的价值。方法:采用平面回波成像(EPI)技术。对50例甲状腺局灶性病变(良性组36例,恶性组14例)行DWI检查,分别测量b值取0、150、300和500s/mm2时良恶性病灶的信号强度和ADC值,并比较其差异。所有患者均经手术(49例)或活检(1例)病理证实。结果:良性与恶性病变的信号强度在b值为0、150、300和500s/mm2时差异均无统计学意义(P>0.05)。b值为150、300和500s/mm2时良性组与恶性组之间ADC值的差异均有统计学意义(P<0.01)。以恶性组ADC值95%可信区间上限作为诊断阈值,则b值为150、300和500s/mm2时,诊断阈值分别为1.992×10-3、1.582×10-3和1.410×10-3mm2/s。应用ROC曲线分析不同b值时ADC阈值诊断恶性病变的作用,显示b值为150s/mm2时价值最大,其诊断敏感度、特异度、符合率、阳性和阴性预测值分别为78.57%、84.62%、82.50%、73.33%和88.00%。结论:甲状腺恶性病变的ADC值低于良性病变,b值取150s/mm2、阈值设为1.992×10-3mm2/s有助于良恶性病变的鉴别。
Objective：To investigate the value of MR diffusion weighted imaging （DWI） in the differential diagnosis of malignant from or benign thyroid lesions. Methods： DWI studies using echo planner imaging （EPI） sequence with a b value of 0,150,300 and 500s/mm2 respectively, as well as routine MRI were performed in 50 patients with pathology proved focal thyroid lesions （ benign, n = 36 ; malignant, n= 14）. The signal intensity （SI） and apparent diffusion coefficient （ADC） values were measured and their differences between these two groups were compared. Results： No statistic differences were existed between the SI of benign and malignant lesions with the b values of 0,150,300 and 500s/mm2 （P〉0.05）. The mean ADC values of benign and malignant lesions showed statistic differences with a b value of 0,150,300 and 500s/mm2 respectively （P〈0.01）. 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 1. 992 ×10^-3 mm2/s. 1. 582 ×10^-3 mm2/s. 1. 410 ×10^-3mm2/s with b values of 150,300 and 500s/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 150s/mm2. The sensitivity, specificity, accuracy, positive predicative value and negative predicative value were 78. 57%, 8,4.62 %, 82.50%, 73.33% and 88.00 %, respectively. Conclusion：The mean ADC value of malignant lesions was lower than that of benign lesions, and ADC value is valuable in differentiating malignant from benign lesions with a threshold of 1.992×10^-3mm2/s and a bvalue of 150s/mm2.
出处
《放射学实践》
北大核心
2009年第7期719-722,共4页
Radiologic Practice
关键词
甲状腺肿瘤
磁共振成像
扩散加权成像
图像处理
计算机辅助
Thyroid neoplasms
Magnetic resonance imaging
Diffusion weighted imaging
Imaging processing, computer-assisted
