3.0T弥散加权成像不同b值评估对前列腺癌的诊断作用

Investigations on B Values in Diffusion-Weighted Imaging for Evaluation of Prostate Cancer at 3T

目的回顾性分析弥散加权成像检查前列腺癌最佳b值,探讨弥散加权成像应用不同b值评估前列腺癌和良性前列腺组织的差别。方法 80例前列腺癌患者行3.0T磁共振弥散加权成像检查,在不同b值行DWI扫描。双盲下分析四种不同b值的ADC图像,测量前列腺癌和良性前列腺组织的ADC值。结果经验丰富医师应用b=1000s/mm2(85%和0.91)敏感性和AUC值明显高于b=300、700、2000s/mm2(P<0.01),缺乏经验医师应用b=700、1000、2000s/mm2的AUC值明显高于b=300s/mm2(P<0.01)。应用b=300、700、1000、b=2000s/mm2的ADC图像上测量前例腺癌平均ADC值分别为(1.33±0.32)×10-3、(1.03±0.23)×10-3、(0.88±0.21)×10-3、(0.68±0.15)×10-3 s/mm2,前列腺癌肿ADC值明显低于前列腺良性组织(P<0.001)。结论弥散加权成像检查前列腺癌最佳b值为1000s/mm2。

Objective To retrospectively study optimal b values in diffusion-weighted imaging (DWI) for diagnosing prostate cancer,and evaluate the utility of DWI with different b values in differentiating be-tween cancers and benign prostatic tissues.Methods Eighty patients with suspected prostate cancer un-derwent MRI including DWI at 3T,followed by radical prostatectomy,while DWI was examined with dif-ferent b values.Four different ADC maps were analyzed independently by double-blind readers.ADC was measured in benign and malignant tissues.Results For presence of 110 prostate cancers,the sensitivity and area under the curve (AUC)detected by an experienced reader was significantly greater at b= 1000 (85% and 0.91)than that at b = 300,700,2000 s/mm2 (P < 0.01).For the less-experienced readers, the AUC was significantly greater at b=700,1000,2000 s/mm2 than that at b=300 s/mm2 (P <0.01). Meanwhile,mean ADCs of the cancers in sequence from b=300 to 2000 s/mm2 were 1.33,1.03,0.88 and 0.68×10-3 s/mm2 ,which were significantly lower than that of benign tissues(P <0.001).Conclusion The optimal b value for DWI for the prostate cancer might be 1000 s/mm2 .