Department of Radiology, Radboud University Nijmegen Medical Centre, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands.
Radiology. 2012 Oct;265(1):260-6. doi: 10.1148/radiol.12112374. Epub 2012 Aug 24.
To determine the interpatient variability of prostate peripheral zone (PZ) apparent diffusion coefficient (ADC) and its effect on the assessment of prostate cancer aggressiveness.
The requirement for institutional review board approval was waived. Intra- and interpatient variation of PZ ADCs was determined by means of repeated measurements of normal ADCs at three magnetic resonance (MR) examinations in a retrospective cohort of 10 consecutive patients who had high prostate-specific antigen levels and negative findings at transrectal ultrasonographically-guided biopsy. In these patients, no signs of PZ cancer were found at all three MR imaging sessions. The effect of interpatient variation on the assessment of prostate cancer aggressiveness was examined in a second retrospective cohort of 51 patients with PZ prostate cancer. Whole-mount step-section pathologic evaluation served as reference standard for placement of regions of interest on tumors and normal PZ. Repeated-measures analysis of variance was used to determine the significance of the interpatient variations in ADCs. Linear logistic regression was used to assess whether incorporating normal PZ ADCs improves the prediction of cancer aggressiveness.
Analysis of variance revealed that interpatient variability (1.2-2.0×10(-3) mm2/sec) was significantly larger than measurement variability (0.068×10(-3) mm2/sec±0.027 [standard deviation]) (P=.0058). Stand-alone tumor ADCs showed an area under the receiver operating characteristic curve (AUC) of 0.91 for discriminating low-grade versus high-grade tumors. Incorporating normal PZ ADC significantly improved the AUC to 0.96 (P=.0401).
PZ ADCs show significant interpatient variation, which has a substantial effect on the prediction of prostate cancer aggressiveness. Correcting this effect results in a significant increase in diagnostic accuracy.
确定前列腺外周带（PZ）表观扩散系数（ADC）的患者间变异性及其对评估前列腺癌侵袭性的影响。
本研究获得机构审查委员会豁免批准。回顾性分析 10 例连续患者的资料，这些患者前列腺特异性抗原水平升高，经直肠超声引导下活检未见异常，在 3 次磁共振（MR）检查中重复测量正常 ADC，以确定 PZ ADC 的患者内和患者间变异性。在所有 3 次 MR 成像检查中，这些患者的 PZ 均未见癌征象。在另一组 51 例 PZ 前列腺癌患者中，研究患者间变异性对评估前列腺癌侵袭性的影响。全器官切片病理检查作为在肿瘤和正常 PZ 上放置感兴趣区的参考标准。采用重复测量方差分析确定 ADC 患者间变异性的显著性。采用线性逻辑回归分析评估纳入正常 PZ ADC 是否能改善对癌症侵袭性的预测。
方差分析显示，患者间变异性（1.2-2.0×10(-3)mm2/sec）明显大于测量变异性（0.068×10(-3)mm2/sec±0.027[标准差]）（P=.0058）。孤立肿瘤 ADC 用于区分低级别和高级别肿瘤的受试者工作特征曲线下面积（AUC）为 0.91。纳入正常 PZ ADC 可显著提高 AUC 至 0.96（P=.0401）。
PZ ADC 存在明显的患者间变异性，对预测前列腺癌侵袭性有很大影响。校正这种影响可显著提高诊断准确性。
