磁共振弥散加权结合直肠B超联合定位经会阴前列腺穿刺90例报告

目的：检测前列腺癌影像学诊断新技术一磁共振弥散加权成像（MRDWI）诊断前列腺癌的准确性（敏感度和特异度），探索TRUS引导的MRDWI图像上可疑病灶穿刺方法，并比较联合MRDWI及TRUS定位与单纯TURS定位经会阴前列腺穿刺活检的准确性。方法：2007年4月～2008年12月间MRDWI或TRUS检查提示可疑前列腺结节的前列腺穿刺患者90例（平均年龄69岁，平均PSA10．9μg／1）；MRI医师、超声医师、泌尿外科医师联合读片确定可疑病灶（MRDwI表观弥散系数减低及B超低回声结节）；穿刺方案为TRUS引导下经会阴可疑病灶穿刺加系统10针前列腺穿刺；MRDWI可疑结节在TRUS图像上的定位方法：在MRDWI上详细定位病灶（病灶直径，病灶中心距中线X，距膀胱颈部L、距前列腺背侧缘距离H），再在TRUS图像上依据L确定病灶所在横断面，根据X及H确定病灶中心，再测量该横断面上病灶中心距B超探头距离O，在通过病灶中心的纵切面上以高于探头平面O的距离平行进针，即可在TRUS图像上实时精确的穿刺到MRDWI可疑结节。穿刺各针标本注明穿刺部位后分瓶送病理检查；统计各针的影像学诊断及对应的病理，分别计算MRDWI和TRUS的敏感度和特异度。结果：共获963条前列腺穿刺组织标本。前列腺癌阳性针数171个，其中MRDWI阳性123个，敏感度为71．9％（123／171），阳性预测值（PPV）54．7％（123／225）；B超阳性39个，敏感度为22．8％（39／171），PPV56．5％（39／69）。阴性针数792个，其中MRDWI阴性690个，特异度为87．1％（690／792），B超阴性762个，特异度为96．2％（762／792）。MRDWI发现而B超未发现90处（52．6％），B超发现而MRDWI未发现6处（3．5％），MRDWI、B超均发现33处，两者均未发现42处（24．6%）。联合定位穿刺敏感度75．4％（129／171），较之传统B超定位敏感度提高52．6％。结论：MR弥散加权成像诊断前列腺癌的初步结果显示准确性较高，敏感度显著优于TRUS。TRUS引导穿刺MRDWI可疑前列腺结节简单、准确、易行，可藉此联合MRDWI及TRUS联合定位进行前列腺穿刺，提高前列腺癌病灶直接穿刺的敏感度。但目前情况下，仍需要结合系统穿刺来减少漏诊率。

MR Diffusion Weighted Imaging and TRUS Jointly Guided Transperineal Prostate Biopsy (Report of 90 Cases)

Objective： To investigate the value of the new technology-magnetic resonance （MR） diffusion weighted imaging （MRDWI） in the diagnosis of prostate cancer （CAP） ;explore how to biopsy the MRDWI suspicious lesion guided by TURS; compare the diagnostic accuracy of prostate biopsy guided by combination of MRDWI and TRUS with only TRUS. Methods： Between April 2007 and Dec 2008, 90 patients（Average age 69, average PSA10.9 μg/L） with suspected prostate cancer underwent TRUS and MRDWI. Physicians from MRI.Ultrasound and urological division study the imaging together and consider the hypo echo or low apparent diffusion coefficient on MRDWI as suspected lesion. Prostate biopsy protocol is suspected lesion directed biopsy plus ten cores systematic biopsy. Management of TRUS guided biopsy the suspected lesion on MRDWI： 1. locate the lesion in detail on MRDWI （measure the distance from central of lesion to bladder neck as L, to centerline of prostate as X, to dorsal margin of prostate as H）. 2 pull back cross section probe by length of L from bladder neck to locate the lesion site on TRUS, define the core of lesion on the cross-section image according to X and H. measure the diagonal distance from core of lesion to probe as O. 3 get to the lesion site correctly in real time by puncturing parallelly O higher than the probe plane on the longitudinal section including the core of lesion. Biopsy specimens are sent to pathological examination separately with defined puncture site. At last, record diagnostic result on MRDWI or TRUS and histological findings of every specimen. Results： Received a total of 963 prostate biopsy specimens, there are 171 cases of positive specimens and 123 cases of positive MRDWI, the sensitivity is 71.9 % （123/171）, positive predictive value is（PPV） 54.7%（123/225）; positive B ultrasound 39 cases,TRUS is 22.8%（39/171）and PPV 56.5% （39/69） respectively; among 792 negative specimens , negative MRDWI results are 690, the specificity is 87.10% （690/792）,TRUS is 96.2% （762/792） ; Among positive specimens ,MRDW1＋TRUS-resuIt is 90（52.6%）, TRUS＋MRDWI-result is 6 （3.5%） ,both positive resuh is 33 （19.3%） ,both negative result is 42（24.6%）. sensitivity of MRDWI and TRUS jointly guided biopsy is 75.4G （129/171）, increasing 52.6% than TRUS alone. Conclusions：The initial result of diagnostic value of MRDWI on prostate cancer shows high accuracy,more sensitive than TRUS. The management of TRUS guided puncture the suspected lesion according to MRDWI is simple and reliable. MRDWI and TRUS jointly guided biopsy can increase the sensitivity of lesion directed biopsy, and systemic biopsy is still necessary now in spite of increased diagnostic accuracy of MRDWI.