目的 :评价前列腺癌穿刺活检后的MR表现及其对MR诊断准确性的影响。方法 :将 10 2例活检证实的前列腺癌患者分为两组 ,A组为活检后 3周内行MR检查者 ,B组为活检后 3周到 1年内行MR检查者。对两组患者的MR表现进行分析 ,并和穿刺病理结果对照 ,研究了MR诊断的准确性。结果 :A组中有 5 1.4% (18/ 35 )出现活检后血肿 ,B组中有 14 .9% (10 / 6 7)出现血肿及其后遗改变 (P 0 .0 1)。和穿刺活检的病理结果对照 ,A组患者MR诊断准确率为 91.4% ,假阳性率为 2 0 .5 % ;B组患者MR诊断准确率为 94.2 % ,假阳性率为 11.4%。两组之间诊断准确率没有显著差异 ,但假阳性率有显著性差异 (P 0 .0 5 )。结论 :前列腺活检后 3周内易出现血肿 ,使MR诊断的假阳性率增高。对前列腺癌的MRI检查应于活检 3周以后或活检之前进行。 Objective: To evaluate the MR findings after prostate biopsy and its effect on the accuracy of MR diagnosis. Methods: 102 cases of prostate cancer confirmed by biopsy were divided into two groups. Group A was performed MR examination within 3 weeks after biopsy, while group B was performed MR examination within 3 weeks to 1 year after biopsy. MR performance of the two groups of patients were analyzed and compared with the results of puncture pathology to study the accuracy of MR diagnosis. Results: There were 5 1.4% (18/35) hematoma in group A, and 14.9% (10/67) hematoma in group B and the posterior hemorrhage in group B (P 0 .0 1). Compared with the pathological results of biopsy, the diagnostic accuracy of MR in group A was 91.4% and the false positive rate was 20.5%. The diagnostic accuracy of MR in group B was 94.2% and the false positive rate was 11.4%. There was no significant difference in diagnostic accuracy between the two groups, but the false positive rate was significantly different (P 0 .0 5). Conclusions: Hematoma is easily seen within 3 weeks after prostate biopsy, which increases the false positive rate of MR diagnosis. MRI examinations of prostate cancer should be performed 3 weeks after biopsy or before biopsy.