目的利用弥散加权成像评估 外周叶前列腺癌包膜外扩散敏感性和分 级。方法 51例患者在前列腺切除术前 行3.0T磁共振检查。由2名放射医师应 用T2WI评估外周叶包膜外扩散情况，应 用ADC图显示及ADC值测量肿瘤和包膜外 扩散情况。病理学专家测量包膜外扩散 的程度。结果 28/102叶发现包膜外扩 散，12例测量≦1mm,11例测量>1mm和 ≦2mm,5例测量>2mm。2名放射医师在 T2WI图上检测每叶具体包膜外扩散准确 性分别为68.6%、74.5%，ADC图分别显示 肿瘤为66.7%、60.8%，ADC值测量分别为 75.5%、69.6%。对于包膜外扩散>2mm，2 名放射医师利用ADC图或测量ADC值的敏 感性为100%，T2WI为80%；对于包膜外扩 散≦2mm，除经验不足放射医师应用T2WI 检出包膜外扩散敏感性为17.4%，2名放 射医师用3种方法检出包膜外扩散敏感性 为58.3%-81.8%。2名放射医师应用3种方 法检出结果一致性分别为0.18、0.37、 0.60。结论 DWI对于评估每个外周叶前 列腺癌包膜外扩散术明显准确于T2WI， 尤其对于经验不足放射医师评估包膜外 扩散2<mm，并且放射医师间评估结果更 为一致。

Objective To assess the utility of diffusion-weighted imaging(DWI) findings as an indirect marker of side-specific risk of extracapsular extension (ECE) of prostate cancer. Methods Fifty-one patients underwent 3Tmagnetic resonance imaging (MRI) before prostatectomy. Radiologists 1 and 2 assessed each side for ECE using T2-weighted imaging (T2WI) and evaluated apparent diffusion coefficient (ADC) maps for the presence of apparent tumor in each lobe and to measure peripheral zone ADC. A uropathologist measured the extent of any ECE. Results In all, 28/102 lobes had ECE, of which 12 measured≦1 mm, 11 measured >1 mm and ≦2 mm, and five measured >2 mm. Sidespecific accuracies for detection of ECE for readers 1 and 2 were respectively on T2WI :68.6% and 74.5%; presence of apparent tumor on ADC map 66.7% and 60.8%; ADC value 75.5% and 69.6%. For ECE>2 mm, both readers achieved 100% sensitivity based on apparent tumor on ADC map or ADC values and 80% sensitivity using T2WI. For detection of ECE≦2 mm, sensitivity for all combinations of the three methods and two readers ranged from 58.3%–81.8%, aside from assessment for ECE using T2WI by the less experienced reader, which exhibited sensitivity of 17.4%. Interreader agreement for the presence of ECE was 0.18 using T2WI, 0.37 using apparent tumor on ADC map, and 0.60 using ADC values. Conclusion Compared with T2WI, DWI had comparable accuracy for side-specific assessment of ECE, greater sensitivity for ECE <2 mm for the less-experienced radiologist,and greater interreader agreement.