Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York, USA.
J Magn Reson Imaging. 2012 Mar;35(3):660-8. doi: 10.1002/jmri.22888. Epub 2011 Nov 8.
To compare the accuracy of standard and revised monoexponential models of diffusion-weighted magnetic resonance imaging (DW-MRI) data for differentiating malignant from benign prostate tissue, using surgical pathology as the reference standard.
The Institutional Review Board waived informed consent for this Health Insurance Portability and Accountability Act (HIPAA)-compliant, retrospective study of 46 patients (median age = 61 years; range: 42-85 years) who underwent DW-MRI between May and December 2008 before radical prostatectomy for biopsy-proven prostate cancer, had no prior treatment, and had whole-mount step-section pathology maps available showing at least one peripheral zone (PZ) lesion >0.1 cm(3) . DW-MRI data were obtained for b-values of 0, 400, and 700 s/mm(2) . Apparent diffusion coefficients (ADCs) were estimated from PZ regions of interest (ROIs) on b = 0, 700 and b = 0, 400 s/mm(2) images, using a standard monoexponential model. The true diffusion coefficient (D) and perfusion fraction (f) were measured using a revised monoexponential model incorporating all three b-values. Areas under receiver operating characteristic curves (AUCs) were calculated to assess the accuracy of individual parameters and a logistic regression model combining D and f (D+f) in distinguishing malignant ROIs; P < 0.05 denoted significance.
ADC(400) (AUC = 0.81, P < 0.0001), ADC(700) (AUC = 0.79, P < 0.0001), D (AUC = 0.71, P = 0.0001) and D + f distinguished malignant from benign ROIs (AUC = 0.82, P < 0.0001), but f did not (AUC = 0.56, P = 0.28); D + f was significantly more accurate than D (P = 0.016) but not more accurate than ADC(400) (P = 0.26) or ADC(700) (P = 0.12).
The true diffusion coefficient provides an additional DW-MRI parameter for distinguishing prostate cancer that is less influenced than the ADC by b-value selection.
使用手术病理作为参考标准，比较标准和修正单指数模型的扩散加权磁共振成像（DW-MRI）数据在区分前列腺良恶性组织中的准确性。
本研究回顾性分析了 46 例患者（中位年龄 61 岁；范围：42-85 岁）的资料，这些患者均于 2008 年 5 月至 12 月在接受根治性前列腺切除术前行 DW-MRI 检查，以证实前列腺癌活检，且没有接受过任何治疗，并提供了全距分段病理图，至少有一个外周区（PZ）病变>0.1cm³。DW-MRI 数据采集的 b 值为 0、400 和 700s/mm²。在 b = 0、700 和 b = 0、400 s/mm² 图像上，从 PZ 感兴趣区（ROI）中使用标准单指数模型来估计表观扩散系数（ADC）。使用结合所有三个 b 值的修正单指数模型来测量真实扩散系数（D）和灌注分数（f）。计算受试者工作特征曲线（ROC）下面积（AUC）以评估各个参数的准确性，并使用结合 D 和 f（D+f）的逻辑回归模型来区分恶性 ROI；P<0.05 表示差异具有统计学意义。
ADC（400）（AUC = 0.81，P<0.0001）、ADC（700）（AUC = 0.79，P<0.0001）、D（AUC = 0.71，P = 0.0001）和 D + f 可区分良恶性 ROI（AUC = 0.82，P<0.0001），但 f 不能（AUC = 0.56，P = 0.28）；D + f 比 D 更准确（P = 0.016），但不如 ADC（400）（P = 0.26）或 ADC（700）（P = 0.12）准确。
真实扩散系数为区分前列腺癌提供了另一个 DW-MRI 参数，其受 b 值选择影响小于 ADC。
