前列腺MR扩散加权成像的应用研究

目的探讨正常前列腺、良性前列腺增生（BPH）和前列腺癌（Pca）的MR扩散加权成像（DWI）和表观扩散系数（ADC）图表现以及ADC值对前列腺癌的鉴别诊断价值．方法对正常前列腺15例、BPH32例、前列腺癌22例进行MR扩散加权成像，分析DWI和ADC图表现．测量不同b值（b=400、500、700、800、1000s／mm^2）下前列腺癌区域、BPH及正常前列腺的中央腺体（CG）及外周带（PZ）的ADC值，并同时测量膀胱区域的ADC值．结果DWI和ADC图能清晰地显示正常前列腺的中央腺体和外周带；BPH在DWI和ADC图上外周带信号较均匀，中央腺体信号欠均匀；b=700s／mm^2时，前列腺癌在DWI图上表现为高信号，ADC图上表现为低信号．b值越高，ADC值越低．b值相同时，各组间膀胱ADC值无统计学差异．正常前列腺中央腺体与外周带的平均ADC值分别为：（1．602±0．275）×10^-3 mm^2／s；和（1．884±0．378）×10^-3 mm^2／s；BPH组中央腺体增生结节与外周带的平均ADC值分别为：（1．514±0．326）×10^-3 mm^2/s和（1．816±0．473）×10^-3 mm^2／s；前列腺癌组前列腺中央腺体非癌灶区与外周带癌灶平均ADC值分别为：（1．499±0．345）×10^-3 mm^2／s和（1．118±0．484）×10^-3 mm^2／s．前列腺癌的ADC值低于正常前列腺及BPH的ADC值，Pca组与正常前列腺组组间差异及Pca组与BPH组组间差异有统计学意义（F=69．909，P=0．00），正常前列腺组与BPH组之间差异无统计学意义（P=0．229）．结论MR扩散加权成像可用于前列腺的检查，能反映病变的病理变化，提供定量诊断信息．前列腺癌的ADC值低于正常组织及BPH的增生组织，ADC值可用于前列腺癌的鉴别诊断．

Application of MR Diffusion Weighted Imaging of Prostate

Objective To describe diffusion weighted imaging （DWI） and apparent diffusion coefficient （ADC） map appearance of the normal prostate, benign hyperplasia （BPH） and prostate cancer （Pca）, and to evaluate ADC values in differential diagnosis of Pca. Methods 15 cases with normal prostate, 32 cases with BPH and 22 cases with Pea were examined by DWI, DWI and ADC map findings were reviewed. ADC values of the marked foci of the Pca patients and ADC values of peripheral zone （PZ） and central glands （CG） voxels in BPH and normal prostate were measured. The ADC values of the bladder were also measured to assess the validity of the method. Results DWI displayed the CG and PZ of the normal prostate. On DWI, PZ of BPH demonstrated homogenous slightly signal intensity （SI） , CG appeared heterogeneous SI. The signal intensity of Pea appeared to be higher in the DWI images while the factor b was greater. When the factor b was constant, the ADC values of bladder among 3 groups had no statistical difference. The mean ADC of the CG, PZ of the normal prostate groups was （1.602±0.275）×10^-3 mm^2/s, （1.884 ± 0.378）×10^-3 mm^2/s, respectively, and （1.514 ± 0.326） ×10^-3 mm^2/s, （1.816 ±0.437）×10^-3 mm^2/s in the BPH groups, respectively, and （1.499 ±0.345） ×10^-3 mm^2/s, （1.118 ± 0.494） ×10^-3 mm^2/s in the Pca groups. The mean ADC of the Pca was significantly lower （F= 69.909, P= 0.000） than that of PZ of the normal prostate and the BPH, but the different between the PZ of the normal prostate and the BPH had no statistical significance （P = 0.229）. Conclusions MR DWI can give quantitative information for pathological changes in BPH and Pca. Both DWI and ADC map can displaywell Pea location and area. ADC value is lower in cancerous tissue than that in healthy tissue of the prostate and in the tissue of BPH. ADC value measured from DWI can he used to differentiate BPH and Pea.