3.0T磁共振扩散张量成像诊断前列腺外周带癌的初步研究

A Preliminary Study of Diagnosing Prostate Cancer in the Peripheral Zone by MR Diffusion Tensor Imaging at 3.0 T

目的应用3.0 T磁共振成像系统探讨扩散张量成像(DTI)诊断前列腺外周带癌的价值。资料与方法搜集在3.0 T MR行前列腺检查并经穿刺活检证实的33例前列腺病变患者资料。扫描序列包括矢、冠、轴位TSET2WI序列及轴位单次激发平面回波成像(SS-EPI)DTI序列,b值采用0和700 s/mm2。扫描图像由两名放射学家进行评估,将前列腺外周带分为六个区域(每侧外周带分为尖部、中部和基底部三部分),根据穿刺结果将每个区域定为癌区或非癌区,测量前列腺外周带癌区和非癌区的表观扩散系数(ADC)值和各向异性分数(FA)值。采用t检验比较两者的ADC和FA值,并对DTI参数建立Logistic回归模型,对ADC、FA值和DTI参数行受试者工作特征(ROC)曲线分析以确定它们区分前列腺外周带癌区和非癌区的效能。结果前列腺外周带癌区及外周带非癌区的ADC值分别为(1.02±0.16)×10-3mm2/s和(1.22±0.14)×10-3mm2/s;FA值分别为0.38±0.09和0.31±0.06,两者差异均具有统计学意义(P<0.0001,P<0.0001)。ADC值、FA值及DTI区分前列腺外周带癌区和非癌区的ROC曲线下面积分别为0.84、0.76和0.86。DTI曲线下面积显著高于FA值(P=0.0009),但DTI和ADC曲线下面积无显著差异(P=0.1595)。结论 DTI有助于诊断前列腺外周带癌。

Objective To investigate the value of MR diffusion tensor imaging（DTI） in the diagnosis of prostate cancer in the peripheral zone.Materials and Methods MR T2 weighted imaging（T2WI） and DTI was performed in 33 cases confirmed by TRUS guided biopsy at 3.0 T MR with an 8 channel cardiac coil.Images were analyzed by two radiologists.ROIs were drawn according to biopsy zones which were apex,midgland,base on each side of the peripheral zone.ADC and FA values of cancerous sextants and noncancerous sextants were compared using independent samples t test.Logistic regression model was generated for DTI parameters.Receiver operating characteristic（ROC） curves were used to compare and determine the ability of ADC,FA and the two values combined in differentiating prostate cancer from noncancerous prostatic tissue in the peripheral zone.Results 16 of 33 cases were confirmed to be malignant while 17 of 33 cases were benign.All the 198 sextants were confirmed by biopsy,including 136 noncancerous sextants and 62 cancerous sextants.There were significant differences between cancerous sextants（1.02±0.16×10-3mm2/s,0.38±0.09） and noncancerous sextants（1.22±0.14×10-3mm2/s,0.31±0.06） for both ADC and FA values（P0.0001,P0.0001,respectively）.Furthermore,ROC curves analysis showed that the area under the ROC curves of ADC,FA and DTI was 0.84,0.76 and 0.86,respectively.Significant differences were noted between the AUC of DTI and FA alone（0.86 vs.0.76,P=0.0009）,but no differences between the AUC of DTI and ADC alone（0.86 vs.0.84,P=0.1595）.Conclusion DTI can be used as a potential tool in diagnosing prostate cancer in the peripheral zone.