High b-value diffusion-weighted images (DWI) are used for detection of clinically significant prostate cancer (csPCa). This study qualitatively and quantitatively compares synthesized DWI (sDWI) to acquired (aDWI) for detection of csPCa. One hundred fifty-one consecutive patients who underwent prostate MRI and biopsy were included in the study. Axial DWI with b = 0, 500, 1000, and 2000 s/mm2 using a 3T clinical scanner using a 32-channel phased-array body coil were acquired. We retrospectively synthesized DWI for b = 2000 s/mm2 via extrapolation based on mono-exponential decay, using b = 0 and b = 500 s/mm2 (sDWI500) and b = 0, b = 500 s/mm2, and b = 1000 s/mm2 (sDWI1000). Differences in signal intensity between sDWI and aDWI were evaluated within different regions of interest (prostate alone, prostate plus 5 mm, 30 mm and 70 mm margin and full field of view). The maximum DWI value within each ROI was evaluated for prediction of csPCa. Classification accuracy was compared to Restriction Spectrum Imaging restriction score (RSIrs), a previously validated biomarker based on multi-exponential DWI. Discrimination of csPCa was evaluated via area under the receiver operating characteristic curve (AUC). Within the prostate, mean ± standard deviation of percent mean differences between sDWI and aDWI signal were -46 ± 35% for sDWI1000 and -67 ± 24% for sDWI500. AUC for aDWI, sDWI500, sDWI1000, and RSIrs within the prostate 0.62[95% confidence interval: 0.53, 0.71], 0.63[0.54, 0.72], 0.65[0.56, 0.73] and 0.78[0.71, 0.86], respectively. sDWI is qualitatively comparable to aDWI within the prostate. However, hyperintense artifacts are introduced with sDWI in the surrounding pelvic tissue that interfere with quantitative cancer detection and might mask metastases. In the prostate, RSIrs yields superior quantitative csPCa detection than sDWI or aDWI.

中文翻译：

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合成和获取的高 b 值扩散加权 MRI 用于检测前列腺癌的比较


高 b 值扩散加权图像 (DWI) 用于检测具有临床意义的前列腺癌 (csPCa)。本研究定性和定量比较了合成 DWI (sDWI) 与采集 (aDWI) 的 csPCa 检测。该研究纳入了 151 名连续接受前列腺 MRI 和活检的患者。使用 32 通道相控阵体线圈的 3T 临床扫描仪获取 b = 0、500、1000 和 2000 s/mm2 的轴向 DWI。我们通过基于单指数衰减的外推法回顾性地合成了 b = 2000 s/mm2 的 DWI，使用 b = 0 和 b = 500 s/mm2 (sDWI500) 以及 b = 0、b = 500 s/mm2 和 b = 1000 s/mm2 (sDWI1000)。在不同感兴趣区域（仅前列腺、前列腺加 5 毫米、30 毫米和 70 毫米边缘以及全视野）内评估 sDWI 和 aDWI 信号强度的差异。评估每个 ROI 内的最大 DWI 值以预测 csPCa。将分类准确性与限制光谱成像限制评分 (RSIrs) 进行比较，RSIrs 是先前基于多指数 DWI 验证的生物标志物。 csPCa 的区分度通过受试者工作特征曲线 (AUC) 下的面积进行评估。在前列腺内，sDWI 和 aDWI 信号之间百分比平均差异的平均值±标准差对于 sDWI1000 为 -46 ± 35%，对于 sDWI500 为 -67 ± 24%。前列腺内 aDWI、sDWI500、sDWI1000 和 RSIrs 的 AUC 分别为 0.62[95% 置信区间：0.53, 0.71]、0.63[0.54, 0.72]、0.65[0.56, 0.73] 和 0.78[0.71, 0.86]。 sDWI 在质量上与前列腺内的 aDWI 相当。然而，sDWI 会在周围盆腔组织中引入高信号伪影，从而干扰定量癌症检测并可能掩盖转移。 在前列腺中，RSIrs 比 sDWI 或 aDWI 产生更好的 csPCa 定量检测结果。