前列腺外周带癌的MRI 6分区定位诊断研究

Sextant localization of prostate cancer in peripheral zone by MRI: correlation with systemic biopsy pathology

目的评价MRI 6分区诊断作为1个独立诊断系统时,对前列腺外周带癌的定位、定性诊断效能。方法不提供任何临床资料,由2名有不同诊断经验的诊断者对80例前列腺外周带480个分区进行独立盲法阅片,针对每个分区做出诊断,分为1是癌、2可能是癌、3不清楚、4可能不是癌、5不是癌5个等级,如果诊断结果是癌,则进一步进行分期。将诊断结果和系统穿刺活检病理结果进行对照研究。结果(1)经病理证实的470个分区中205个分区为癌。诊断界值取2时,MRI 6分区诊断和穿刺病理的一致性较好,Kappa值为0．549-0．560,准确度78．1％-78．3％,敏感度69．3％-76．1％,特异度84．9％-80．0％,阳性预测值78．0％-74．6％,阴性预测值78．1％- 81．2％。(2)不同经验的诊断者的ROC曲线下面积分别为0．829±0．020和0．840±0．019,两者间(U=-0．3988,P>0．05)诊断效能差异无统计学意义。结论MRI可用于前列腺癌的定位、定性诊断,但准确性有待进一步提高。

Objective To determine the efficacy of sextant localization of prostate cancer （PCa） in PZ （peripheral zone） by MR Imaging. Methods Fifty-one cases of PCa and 29 cases of benign prostate diseases were enrolled in the study. Each peripheral zone was divided into 6 sections （ left/right bottom, middle and tip ） in the same fashion for biopsy and the characteristics of each sextant was evaluated separately. Being blinded to clinical data, 2 radiologists with different subspecialty experience analyzed MR images of the 480 sections of these 80 cases retrospectively. Each sextant region impression of likelihood for cancer was estimated by the rank of a five-point rating scale （ 1 = definite PCa, 2 = probable PCa, 3 = possible PCa, 4 = probably not PCa, 5 = definitely not PCa）. If definite PCa was considered, then it was staged furthermore. Each diagnosis of sextant region was compared with the pathological result of corresponding biopsy site. Result （ 1 ） Four hundred and seventy sections （205 cancerous and 265 benign） were proved by biopsy. The diagnosis efficacy was best when cutoff point was 2. There was moderate consistency between the results of MRI and pathology with the kappa value of 0. 549 - 0. 560. The total accuracy was 78. 1% - 78. 3% with the sensitivity of 69. 3% - 76. 1% and the specificity of 84.9% - 80. 0%. The positive predictive value was 78.0% -74. 6% and the negative predictive value was 78. 1% - 81.2%. （2） The ROC analysis demonstrated that Az with total impression recorded by two readers had not significant difference（0.829±0.020 vs. 0.840±0.019, U= -0.3988,P〉0.05）.Conclusion MRI may be an elementary way to localize PCa in PZ, but the diagnosis efficacy need to be improved furthermore.