前列腺磁共振扩散加权成像的初步研究

Diffusion-weighted MR imaging of the prostate:preliminary study

目的探讨MR扩散加权成像对正常前列腺外周带、炎症和癌的诊断价值。方法收集13例良性前列腺增生、10例前列腺炎和15例前列腺外周带癌患者的MR检查资料。将前列腺外周带以六分区法划分,依病理结果将其分为正常区、炎症区及癌区。所有病人行单次激发EPI序列的MR扩散成像检查,b值分别取300、500、800s/mm2。观察DWI图,并测量外周带各分区内及每位患者的闭孔内肌和膀胱内表观扩散系数(ADC)值,并对所得数值进行双样本方差分析。结果13例良性前列腺增生、8例前列腺炎及14例前列腺癌获得可靠ADC值。b=800s/mm2时,前列腺癌在DWI图像上表现为较高信号。b值越高,ADC值越低。b值相同时,各组间闭孔内肌及膀胱ADC值无统计学差异。b=800s/mm2时,正常外周带平均ADC值(2.15±0.31)×10-3mm2/s,炎症区平均ADC值(2.12±0.33)×10-3mm2/s,癌区平均ADC值(1.17±0.21)×10-3mm2/s,癌组与正常组组间差异及炎症组与癌组组间差异具有统计学意义(F=188.61,P=0.00),炎症区与正常区之间无统计学差异(P=0.53)。结论MR扩散加权成像的ADC值有可能用于前列腺炎与癌的鉴别。

Objective To evaluate whether diffusion weighted imaging （DWI） can be used to differentiate prostate adenocarcinoma （PCa） from normal prostate peripheral zone （PZ） and prostatitis. Methods DWI was performed in 3 groups, 13 benign prostate hypertrophy （BPH） patients, 10 prostatitis patients and 15 PCa patients. All of the prostatitis patients and PCa patients were proved by systemic ultrasound guided biopsy. The locations of the tumor were marked by the pathologist. DWI were obtained with 3 different diffusion factors, factor b, of 300, 500 and 800 s/mm^2. Each PZ was divided into 6 regions in apparent diffusion coefficients （ADC） map and the ADC values were measured in each region by drawing the regions of interest （ROIs）. The ADC values of the bladder and the obturator internus were also measured to assess the validity of the method. Results Acceptable images for ADC measurement were obtained in 35 （92.1%） patients （13 BPH, 8 prostatitis and 14 PCa）. The intensity of PCa appeared to be higher in the DW images while the factor b was greater. When the fac- tor b was constant, the ADC values of the bladder and the obturator internus among 3 groups had no statistical difference, respectively. When b=800 s/mm^2 , the mean ADC values of all normal regions, and that of all inflammation regions and that of all cancerROIs, were （2.15±0.31）, （2.12±0.33） and （1. 17±0.21）×10^-3 mm^2/s respectively. The mean ADC of PCa was significantly smaller （F= 188. 61, P=0.00） than that of normal PZ of the prostate and the prostatitis, but the difference between the inflammation regions and the normal PZ had no statistical significance （P=0.53）. Conclusion ADC value measured from DWI can be used to differentiate prostatitis and PCa.