表观扩散系数鉴别前列腺中央腺体癌和前列腺增生的价值

目的探讨表观扩散系数（ADC）在鉴别中央腺体（CG）区前列腺癌（PCa）和前列腺增生（BPH）的价值。方法收集行DWI检查并经病理证实的CG区PCa和BPH各23例,分别为PCa组和BPH组,DWI序列b值分别取300、500和800s/mm2并自动生成ADC图。测量不同b值条件下各组DWI图像信噪比（SNR）和病灶的ADC值,采用配对t检验比较相同病灶不同b值时SNR和ADC有无差异,独立样本t检验比较相同b值时PCa和BPH的ADC值有无差异,并利用ROC分析ADC鉴别PCa和BPH的曲线下面积（Az）、敏感性和特异性。结果 CG区PCa在DWI呈高信号,ADC值减低。不同b值时,DWI图像的SNR之间及相同病灶的ADC值之间均具有显著性差异（P〈0.001）;相同b值条件下,PCa和BPH的ADC之间均具有显著性差异（P〈0.001）;b=300、500、800s/mm2时,Az分别为0.89、0.91、0.94;b=800s/mm2时取最佳临界值为1.305,敏感性、特异性均达87%。结论CG区PCa病灶区ADC值明显下降,与BPH表现具有显著差异;ADC值有助于CG区PCa和BPH的鉴别,对于提高CG区PCa的检出率具有重大意义。

Value of apparent diffusion coefficient to differentiate prostate cancer in central gland from benign prostate hyperplasia

Objective：To evaluate the ability of apparent diffusion coeffi cient （ADC） to differentiate prostate cancer （PCa） of the central gland （CG） from benign prostate hyperplasia （BPH）.Materials and Methods：Twenty-three PCa cases of CG and 23 BPH cases were divided into PCa group and BPH group,who had been performed MR diffusion weighted imaging （DWI） and pathologically conf irmed.DWI sequence was performed with three b values （300,500,and 800 s/mm2）,and ADC map was automatically generated.Signal-to-noise ratio （SNR） of DW images and the ADC values of the same lesion in each group were measured under different b values,and paired t test was used to verify the difference of SNR and the ADC values of the same lesions with different b values.Independent sample t test was used to verify the difference of the ADC values between PCa and BPH with the same b value.ROC analysis was used and the area under the curve （Az）,sensitivity and specif icity were calculated.Results：PCa lesions of CG were presented with hyperintensity on DWI and hypointensity on ADC map.The difference of SNR and the ADC values of the same lesions with different b values were of statistic signifi cance （P0.001）;ADC values between PCa and BPH with the same b value were of statistic significant difference （P0.001）.When b=300,500,800 s/mm2,Az of the ROC was 0.89,0.91,0.94,respectively.The sensitivity and specif icity of ADC value to identify PCa from BPH both reached 87% when b=800 s/mm2 with the cutoff of 1.305.Conclusion：ADC value of PCa lesions of CG decreases commonly,with signif icant differences with that of BPH,which makes ADC value signif icant to differentiate PCa of CG with BPH.