Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710, Korea.
Korean J Radiol. 2013 Jan-Feb;14(1):61-9. doi: 10.3348/kjr.2013.14.1.61. Epub 2012 Dec 28.
To retrospectively determine the optimal b value of diffusion-weighted imaging (DWI) for predicting the presence of localized prostate cancer, and to evaluate the utility of DWI under different b values in differentiating between cancers and benign prostatic tissues.
Eighty patients with suspected prostate cancer underwent MRI including DWI at 3T, followed by radical prostatectomy. DWI was examined under different b values. Apparent diffusion coefficient (ADC) maps were generated by using b = 0, and other b values of 300, 700, 1000 or 2000 s/mm(2). For predicting the presence of cancers, four different ADC maps were analyzed independently by two blinded readers. ADCs were measured in benign and malignant tissues.
For predicting the presence of 110 prostate cancers, the sensitivity and area under the curve (AUC) for an experienced reader was significantly greater at b = 1000 (85% and 0.91) than b = 300, 700 or 2000 s/mm(2) (p < 0.01). For a less-experienced reader, the AUC was significantly greater at b = 700, 1000 or 2000 than b = 300 s/mm(2) (p < 0.01). Mean ADCs of the cancers in sequence from b = 300 to 2000 s/mm(2) were 1.33, 1.03, 0.88 and 0.68 × 10(-3) mm(2)/s, which were significantly lower than those of benign tissues (p < 0.001).
The optimal b value for 3T DWI for predicting the presence of prostate cancer may be 1000 s/mm(2).
回顾性确定扩散加权成像（DWI）预测局限性前列腺癌存在的最佳 b 值，并评估不同 b 值下 DWI 在区分癌症与良性前列腺组织中的作用。
80 例疑似前列腺癌患者在 3T 磁共振成像（MRI）下行 DWI 检查，随后行根治性前列腺切除术。在不同的 b 值下进行 DWI 检查。采用 b = 0 和其他 b 值（300、700、1000 或 2000 s/mm2）生成表观扩散系数（ADC）图。为预测癌症的存在，两位盲法阅片者分别独立分析 4 种不同的 ADC 图。在良性和恶性组织中测量 ADC。
在预测 110 例前列腺癌的存在时，有经验的阅片者在 b = 1000 时的敏感性和曲线下面积（AUC）显著大于 b = 300、700 或 2000 s/mm2（p < 0.01）。对于经验较少的阅片者，b = 700、1000 或 2000 时的 AUC 显著大于 b = 300 s/mm2（p < 0.01）。b 值依次从 300 到 2000 s/mm2 时，癌症的平均 ADC 分别为 1.33、1.03、0.88 和 0.68×10-3 mm2/s，显著低于良性组织（p < 0.001）。
3T DWI 预测前列腺癌存在的最佳 b 值可能为 1000 s/mm2。
