以穿刺活检为金标准对前列腺MRS检查评价指标选择的研究

目的 探讨方便实用的术前诊断前列腺癌的MRS半定量指标.方法 选择行前列腺MRS检查并经穿刺活检病理证实、临床资料齐全的初诊前列腺疾病患者100例进行MRS分析,测量可用体素的(胆碱+肌酸)枸椽酸盐(Cho+Cr)/Cit]值,并计算前列腺外周带各分区的(Cho+Cr)/Cit平均值、阳性体素比及整个前列腺(Cho+Cr)/Cit平均值、阳性体素比最大值和阳性体素比平均值,分别在6分区中的每个分区和前列腺整体水平评价各种指标诊断前列腺癌的效能,并分别利用配对卡方检验和Kappa检验判断各指标诊断前列腺癌准确性的差异和一致性.结果 100例共获得符合可用标准的体素2945个,其中前列腺癌区1203个,非前列腺癌区1742个,癌区体素(Cho+Cr)/Cit值范围0.22～8.00,中位数为1.87;非癌区体素(Cho+Cr)/Cit值范围0.11～8.00,中位数为0.53,癌区体素的(Cho+Cr)/Cit值大于非癌区(Z=28.48,P<0.01),但有部分重叠.在分区水平,应用如下MRS指标诊断前列腺癌的敏感性、特异性、阳性预测值、阴性预测值和准确性为:(1)以单个体素(Cho+Cr)/Cit值>0.911为标准时:81.4%(179/220)、64.2%(194/302)、62.4%(179/287)、82.6%(194/235)、71.5%(373/522);(2)以(Cho+Cr)/Cit平均值>0.911为标准时:77.3%(170/220)、77.2%(233/302)、71.1%(170/239)、82.3%(233/283)、77.2%(403/522);(3)以阳性体素比>0.519为标准时:73.2%(161/220)、80.8%(244/302)、73.5%(161/219)、80.8%(244/302)、77.6%(405/522).其中(Cho+Cr)/Cit平均值和阳性体素比一致性较高(Kappa=0.907).在整体水平,上述值分别为:(1)以单个体素(Cho+Cr)/Cit值>0.911为标准时:94.3%(50/53)、40.4%(19/47)、64.1%(50/78)、86.4%(19/22)、69.0%(69/100);(2)以(Cho+Cr)/Cit平均值>0.911为标准时:73.6%(39/53)、83.0%(39/47)、83.0%(39/47)、73.6%(39/53)、78.0%(78/100);(3)以阳性体素比最大值>0.519为标准时:88.7%(47/53)、61.7%(29/47)、72.3%(47/65)、82.9%(29/35)、76.0%(76/100);(4)以阳性体素比平均值>0.519为标准时:62.3%(33/53)、85.1%(40/47)、82.5%(33/40)、66.7%(40/60)、73.0%(73/100).其中(Cho+Cr)/Cit平均值与阳性体素比平均值之间一致性较高(Kappa=0.818).结论 诊断临床可疑前列腺癌人群时建议选用单个体素标准,用于指导穿刺活检定位时建议选用阳性体素比最大值标准.

Evaluation of semi-quantitative parameters of prostate MR spectroscopy: comparison with biopsy

Objective To explore convenient and practical semi-quantitative MRS indicators in diagnosis of prostate cancer.Methods One hundred patients with completer MRS data and clinical data were enrolled in the study.The following parameters were assessed to evaluate their efficacy in diagnosis of prostate cancer, (Cho + Cr)/Cit of single voxel, mean (Cho + Cr)/Cit of the whole area and (Cho + Cr)/ Cit positive voxel ratio at the sextant level.Similarly, all the parameters mentioned above and mean (Cho +Cr)/Cit positive voxel ratios of the whole gland were assessed at the whole gland level.Pearson test and Kappa test were used in the research.Results Two thousand nine hundred and forty-five voxels were assessed including 1203 in cancer positive region and 1742 in cancer negative regioa The range of the (Cho + Cr) /Cit ratio in cancer positive region was from 0.22 to 8.00 (median, 1.87), and that in cancer negative region was from 0.11 to 8.00 (median, 0.53).The (Cho + Cr)/Cit ratio in cancer positive region was higher than that in cancer negative region (Z =28.48, P<0.01) with partial overlap.On the level of sextant, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of (Cho + Cr)/Cit ratio> 0.911 to diagnose prostate cancer were 81.4% (179/220),64.2% (194/302), 62.4% (179/287) 、82.6% (194/235) 、71.5% (373/522) respectively; those of mean (Cho + Cr)/Cit ratio>0.911 were 77.3% (170/220),77.2% (233/302),71.1% (170/239),82.3% (233/283),77.2% (403/522) respectively; those of positive voxel ratio>0.519 were 73.2% (161/220),80.8% (244/302)、 73.5% (161/219),80.8% (244/302), 77.6% (405/522) respectively; the consistency between mean (Cho + Cr) /Cit ratio and positive voxel ratio was high (Kappa=0.907).On the level of the whole prostate, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of (Cho + Cr)/ Cit ratio>0.911 to diagnose prostate cancer were 94.3% (50/53),40.4% (19/47),64.1% (50/78), 86.4% (19/22),69.0% (69/100) respectively; those of mean (Cho + Cr)/Cit ratio>0.911 were73.6% (39/53),83.0% (39/47), 83.0% (39/47), 73.6% (39/53), 78.0% (78/100) respectively; those of maximum positive voxel ratio> 0.519 were 88.7% (47/53),61.7% (29/47),72.3% (47/65),82.9% (29/35),76.0% (76/100) respectively; those of mean positive voxel ratio>0.519 were 62.3% (33/53), 85.1% (40/47), 82.5% (33/40), 66.7% (40/60), 73.0% (73/100) respectively; the consistency between mean (Cho + Cr)/Cit ratio and mean positive voxel ratio was fairly high (Kappa =0.818).Conclusion Single voxel criteria were suggested to diagnose clinically suspected prostate cancer.Maximum positive voxel ratio criteria were suggested to guide localization in biopsy.