(1) Background: We assessed the test–re-test repeatability of radiomics in metastatic castration-resistant prostate cancer (mCPRC) bone disease on whole-body diffusion-weighted (DWI) and T1-weighted Dixon MRI. (2) Methods: In 10 mCRPC patients, 1.5 T MRI, including DWI and T1-weighted gradient-echo Dixon sequences, was performed twice on the same day. Apparent diffusion coefficient (ADC) and relative fat-fraction-percentage (rFF%) maps were calculated. Per study, up to 10 target bone metastases were manually delineated on DWI and Dixon images. All 106 radiomic features included in the Pyradiomics toolbox were derived for each target volume from the ADC and rFF% maps. To account for inter- and intra-patient measurement repeatability, the log-transformed individual target measurements were fitted to a hierarchical model, represented as a Bayesian network. Repeatability measurements, including the intraclass correlation coefficient (ICC), were derived. Feature ICCs were compared with mean ADC and rFF ICCs. (3) Results: A total of 65 DWI and 47 rFF% targets were analysed. There was no significant bias for any features. Pairwise correlation revealed fifteen ADC and fourteen rFF% feature sub-groups, without specific patterns between feature classes. The median intra-patient ICC was generally higher than the inter-patient ICC. Features that describe extremes in voxel values (minimum, maximum, range, skewness, and kurtosis) showed generally lower ICCs. Several mostly shape-based texture features were identified, which showed high inter- and intra-patient ICCs when compared with the mean ADC or mean rFF%, respectively. (4) Conclusions: Pyradiomics texture features of mCRPC bone metastases varied greatly in inter- and intra-patient repeatability. Several features demonstrated good repeatability, allowing for further exploration as diagnostic parameters in mCRPC bone disease.
(1) 背景：本研究评估了基于全身扩散加权成像（DWI）与T1加权Dixon磁共振成像的影像组学特征在转移性去势抵抗性前列腺癌骨转移病灶中的重测可重复性。(2) 方法：对10例mCRPC患者于同日内进行两次1.5T磁共振扫描（包含DWI与T1加权梯度回波Dixon序列），计算表观扩散系数图及相对脂肪分数百分比图。每次研究中，在DWI与Dixon图像上手动勾画最多10个目标骨转移灶。使用Pyradiomics工具包从ADC与rFF%图中提取全部106个影像组学特征。为评估患者间与患者内测量可重复性，将经对数转换的个体靶区测量值拟合至分层模型（以贝叶斯网络表示），计算包括组内相关系数在内的可重复性指标，并将特征ICC与平均ADC及平均rFF%的ICC进行比较。(3) 结果：共分析65个DWI靶区与47个rFF%靶区。所有特征均未出现显著偏倚。配对相关性分析显示ADC特征形成15个子群，rFF%特征形成14个子群，特征类别间未呈现特定规律。患者内ICC中位数普遍高于患者间ICC。描述体素值极值（最小值、最大值、极差、偏度、峰度）的特征普遍呈现较低ICC。研究发现若干主要基于形态的纹理特征，其患者间与患者内ICC分别较平均ADC或平均rFF%更高。(4) 结论：mCRPC骨转移灶的Pyradiomics纹理特征在患者间与患者内可重复性差异显著。部分特征展现出良好可重复性，可作为mCRPC骨疾病的诊断参数进行深入探索。
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