弥散加权成像对前列腺癌包膜外扩散程度分级的应用价值

Utility of Diffusion-weighted Imaging to Grading Extracapsular Extension with Prostate Cancer

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（DWl） findings as an indirect marker of side-specific risk of extracapsular extension （ECE） of prostate cancer. Met：hods Fifty-one patients underwent 3T magnetic resonance imaging （MRl） before prostatectomy. Radiologists 1 and 2 assessed each side for ECE using T2-weighted imaging （T2WI） and evaluated apparent diffilsion coefficient （ADC） maps for the presence of apparent tunmr 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 ram, 11 measured 〉1 mm and ≤2 nnn, and five measured 〉2 ram. Side- specific 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 ram, both readers achieved 100% sensitivity based on apparent tumor on AI）C map or ADC values and 80% sensitivity using T2WI. For detection of ECE 〈 2 ram, 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 nsing apparent tumor on ADC map, and 0.60 using ADC values. Condusion 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.