磁共振DWI结合T2加权成像诊断前列腺癌侵犯精囊腺

目的：探讨分别应用T2WI、DWI以及综合应用这2种成像序列对前列腺癌（PCa）侵犯精囊腺（SVI）的诊断价值。方法：对50例PCa患者行MR前列腺常规和DWI扫描,所有患者经前列腺癌根治术证实,其中21例伴有SVI。分析PCa癌灶、SVI和正常精囊腺（SV）的MRI表现,比较其ADC值。采用5分制评分,将所得结果与病理结果对照,采用SPSS11.5分别绘制受试者工作特征曲线（ROC）,分析比较各组方法诊断的敏感度和特异度。结果：PCa癌灶、SVI和SV的ADC值分别为（0.940±0.122）×10^-3 mm2/s、（1.025±0.186）×10^-3 mm2/s和（2.798±0.248）×10^-3 mm2/s,SVI的ADC值明显低于SV（P〈0.05）,而PCa癌灶和SVI的ADC值之间无明显差异（P=0.20）。分别应用T2WI和DWI诊断SVI的ROC曲线下面积（AUC）明显低于联合应用2种成像方法（P〈0.05）。结论：SVI的ADC值明显低于SV;联合应用2种成像序列诊断SVI优于单独使用T2WI或DWI。

Diagnosis of Seminal Vesicle Invasion in Prostate Carcinoma by Magnetic Resonance DWI Combined with T2-Weighted Imaging

Objective To retrospectively determine the diffusion weighted imaging（DWI） characteristics and apparent diffusion coefficient（ADC） values of prostate carcinoma（PCa） with seminal vesicle invasion（SVI）,and to compare the accuracy of T2-weighted MRI alone and T2 combined with DWI for predicting SVI.Methods 50 patients underwent conventional MRI and DWI before prostate cancer surgery.DWI and ADC map appearances of all PCa foci,SVI and seminal vesicle（SV） were analyzed,and their ADC values were measured.T2 images alone and then T2 images combined with DWI were scored for the likelihood of SVI on the basis of radiologists＇ written reports.The area under the receiver operating characteristic curve（AUC） was used to assess sensitivity and specificity.Statistical significance was inferred at P0.05.Results At pathologic analysis,21（42%） of 50 patients had SVI.The mean ADCs for PCa foci,SVI and SV were（0.940±0.122）×10-3 mm2·s-1,（1.025±0.186）×10-3 mm2·s-1 and（2.798±0.248）×10-3 mm2·s-1,respectively.The ADC values of SVI were significantly lower than those of SV.The AUC for T2 weighted imaging plus DW imaging（0.829） was significantly larger（P〈0.05） than that for T2 weighted imaging alone（0.722） or for DW imaging alone（0.695）.Conclusion SVI has lower ADC values than SV.T2 images plus DWI is significantly better than T2-weighted imaging alone in the detection of SVI.