运用多b值DWI探讨前列腺中央腺体癌的诊断

To Investigate the Diagnosis of Prostate Central Gland Cancer by Multiple B Values DWI

目的运用3.0 T MR多b值DWI探讨b值选择对前列腺中央腺体癌(CGPCa)及良性前列腺增生(BPH)鉴别效能的影响。方法经病理证实的28例CGPCa及23例BPH患者行常规序列及DWI序列扫描,DWI设定4个b值(0、500、1000、1500 s/mm^2),分别选取b=0、1000 s/mm^2,b=0、500、1000 s/mm^2,b=0、1500 s/mm^2,b=0、500、1500 s/mm^2,b=0、1000、1500 s/mm^2,b=0、500、1000、1500 s/mm^2拟合得到ADC图,测量感兴趣区域(ROI)的ADC值。采用两独立样本t检验比较CGPCa组与BPH组ADC值的差异,应用受试者工作特征(ROC)曲线评价不同b值组合的诊断效能。结果 b=0、1000 s/mm^2和b=0、500、1000 s/mm^2两组在CGPCa及BPH组各ROI的ADC值均相等。CGPCa及BPH组在不同b值组合下ADC值差异均有显著统计学意义(P<0.001)。b=0、1000 s/mm^2,b=0、500、1000 s/mm^2,b=0、1500 s/mm^2,b=0、500、1500 s/mm^2,b=0、1000、1500 s/mm^2,b=0、500、1000、1500 s/mm^2的曲线下面积(AUC)分别为0.912、0.912、0.952、0.950、0.952、0.950;两两比较显示b=0、1500s/mm^2,b=0、1000、1500 s/mm^2,b=0、500、1000、1500 s/mm^2三组分别与b=0、1000 s/mm^2和b=0、500、1000 s/mm^2组的AUC比较差异有统计学意义,P值分别为0.015、0.009、0.015。在b=0、1500 s/mm^2组,当ADC值阈值为0.901×10^(-3)mm^2/s时,诊断CGPCa的敏感性为92.86%,特异性为100%,阳性预测值为100%,阴性预测值为85.2%。结论 b=1500 s/mm^2的高b值DWI对于鉴别CGPCa与BPH具有显著意义,诊断效能优于b=1000 s/mm^2的常规DWI。

Objective To investigate the effect of bvalue on differentiation efficiency of prostate central gland cancer（CGPCa） and benign prostate hyperplasia（BPH） by using multiple bvalues diffusion weighted imaging（DWI）.Methods28 cases of PCa and 23 cases of BPHproved by histopathology were examined by routine sequences and DWI pulse sequence.The diffusion bvalues were 0,500,1000 and 1500 s/mm^2.ADC map was fitted by using b = 0,1000 s/mm^2,b =0,500,1000 s/mm^2,b = 0,1500 s/mm^2,b = 0,500,1500 s/mm^2,b = 0,1000,1500 s/mm^2,b = 0,500,1000 and1500 s/mm^2,respectively,and the ADC value in ROI（Region of Interest） was measured.Two-sample t-test was used to compare ADC values between CGPCa and BPH groups.The diagnostic performance of ADC values was evaluated with receiver operating characteristics（ROC）.Results ADC（b = 0,1000 s/mm^2） and ADC（b = 0,500,1000 s/mm^2） in any CGPCa and BPH cases was completely equaled.The ADC values from six kinds of b value combinations had statistically significant difference between CGPCa and BPH groups（P 〈0.001）.The area under the ROC curve for ADC（b = 0 and 1000 s/mm^2）,ADC（b = 0,500 and 1000 s/mm^2）,ADC（b = 0 and 1500 s/mm^2）,ADC（b = 0,500 and 1500 s/mm^2）,ADC（b= 0,1000 and 1500 s/mm^2）,ADC（b = 0,500,1000 and 1500 s/mm^2） was 0.912,0.912,0.952,0.950,0.952,0.950,respectively.Comparison of ROC curves shown statistically significance in ADC（b = 0.1000 s/mm^2） or ADC（b = 0,500 and 1000 s/mm^2） with three other combinations including ADC（b = 0,1500 s/mm^2）,ADC（b = 0,1000 and 1500 s/mm^2） and ADC（b = 0,500,1000,1500 s/mm^2）,P value was 0.015,0.009,0.015,respectively.According to the ROC analysis; when the cutoff value was 0.901×10- 3mm^2/s in the combination of b = 0.1500 s/mm^2,the sensitivity,specificity,positive predictive value,and negative predictive value of diagnosing CGPCa were 92.86%,100%,100%,85.2%,respectively.Conclusion High b value（b = 1500 s/mm^2） DWI had certain significance in differentiating the CGPCa and BPH,and high b value（b = 1500 s/mm^2） DWI was superior to the conventional DWI（b = 1000 s/mm^2） on diagnosis efficiency.