DWI、T_2加权像及综合应用对前列腺癌诊断价值的研究

MR evaluation of prostate cancer:comparison of T2-weighted Imaging,diffusion-weighted imaging,and combined two MRI techniques

目的:通过对分别应用T2WI及DWI两种成像方法及其综合应用对前列腺癌进行定性诊断的比较,探讨两种方法各自及综合应用对前列腺癌的诊断价值。方法:应用1.5T MR成像仪对42例前列腺疾病患者进行前列腺磁共振高分辨成像,其中前列腺癌15例,良性病变包括良性前列腺增生及慢性前列腺炎症等27例。在MRI常规成像基础上行DWI扫描,扩散敏感系数(b)值分别为0、1000s/mm2。采用盲法阅片,按照前列腺6分区法将两种MR技术分别所得图像数据分区评估测量并采用5分制评分,根据两种技术的5分制评分进行T2加权像综合DWI方法评分,将所得结果与病理结果对照。利用SPSS 11.5分别做ROC曲线分析比较,计算各组方法诊断的敏感度、特异度及准确度等。结果:各组诊断方法的敏感度、特异度及ROC曲线下面积(Az)如下:T2WI:88.2%,67.2%和0.848±0.030,最佳诊断界值为3;ADC诊断:82.4%,81.6%和0.860±0.033,最佳界值为4;ADC结合T2WI诊断:78.4%,92.5%和0.922±0.021,最佳界值为4.结论:通过独立评估T2WI及DWI两种方法均可以有效诊断前列腺癌;两种成像方法综合应用诊断前列腺癌的准确度显著高于两种成像技术独立诊断,其诊断结果与病理分析一致性较好。

Objective： To investigate the value of diagnosis for prostate cancer through both histopathology and MRI findings by using T2-weighted imaging and diffusion-weighted imaging respectively and combination of two MRI techniques. Methods： MR images were perfomed in 42 cases. T2WI and DWI were achieved by 1.5T MR. The ADC maps were obtained with two b-values （0 and 1000 seconds/ mm2）. All the cases were quantitatively assessed by two imaging methods respectively, then by the combined DWI ＋ T2WI. The diagnosed indexes and the receiver operating characteristic（ROC） curve analysis of each method were taken for the comparison corresponding with the result of systemic biopsy as the standard of reference. Results： The diagnostic performance of each protocol： The sensitivity and specificity for the detection of prostate cancer were 88.2% and 67.2% for T2WI as the cut-eft was 3; 82.4% and 81.6% for DWI as the cut-off was 4; 78.4% and 92.5% for the combined DWI ＋ T2WI as the cut-off was 4. In the ROC analyses, the area under the ROC curve（Az） were 0. 848 ± 0.030 and 0.860 ± 0.033 for T2WI and DWI respectively, and was 0.922 ± 0.021 for the combined of T2WI ＋ DWI. Conclusion： 1. Prostate cancer could be effectively diagnosed with T2WI and DWI respectively. 2.The combination of the two techniques increases the accuracy in the detection of prostate cancer.