Wong Oi Lei, Yuan JIng, Zhou Yihang, Yu Siu Ki, Cheung Kin Yin
Medical Physics and Research Department, Hong Kong Sanatorium & Hospital, Happy Valley, Hong Kong SAR, China.
Med Phys. 2021 Mar;48(3):1239-1249. doi: 10.1002/mp.14686. Epub 2021 Feb 2.
The purpose of this study was to quantitatively assess the longitudinal acquisition repeatability of MRI radiomics features in a three-dimensional (3D) T1-weighted (T1W) TSE sequence via a well-controlled prospective phantom study.
Thirty consecutive daily datasets of an ACR-MRI phantom were acquired on two 1.5T MRI simulators using a 3D T1W TSE sequence. Images were blindly segmented by two observers. Post-acquisition processing was minimized but an intensity discretization (fixed bin size of 25). One hundred and one radiomics features (shape n = 12; first order n = 16; texture n = 73) were extracted. Longitudinal repeatability of each feature was evaluated by Pearson correlation and coefficient of variance (CV ). Interobserver feature value agreement was also quantified using intraclass correlation coefficient (ICC) and Bland-Altman analysis. A most repeatable radiomics feature set on both scanners was determined by feature coefficient of variance (CV <5%), ICC (>0.75), and the ratio of the interobserver difference to the interobserver mean δ<5%.
No trend of radiomics feature value changed with time. Longitudinal feature repeatability CV ranged 0.01-38.60% (mean/median: 12.5%/9.9%), and 0.01-40.47%, (8.49%/7.34%) on the scanners A and B. Shape features exhibited significantly better repeatability than first-order and texture features (all P < 0.01). Significant longitudinal repeatability difference was observed in texture features (P < 0.001) between the two scanners, but not in shape and first-order features (P > 0.30). First-order and texture features had smaller interobserver-dependent variation than acquisition-dependent variation. They also showed good interobserver agreement on both scanners (A:ICC = 0.80 ± 0.23; B:ICC = 0.80 ± 0.22), independent of acquisition repeatability. The repeatable radiomics features in common on both scanners, including 12 shape features, 0 first-order features, and 3 texture features, were determined as the most repeatable MRI radiomics feature set.
Radiomics features exhibited heterogeneous longitudinal repeatability, while the shape features were the most repeatable, in this phantom study with a 3D T1W TSE acquisition. The most repeatable radiomics feature set derived in this study should be helpful for the selection of reliable radiomics features in the future clinical use.
本研究的目的是通过一项严格控制的前瞻性体模研究，定量评估三维（3D）T1加权（T1W）快速自旋回波（TSE）序列中MRI影像组学特征的纵向采集重复性。
使用3D T1W TSE序列在两台1.5T MRI模拟机上连续采集30个ACR-MRI体模的每日数据集。图像由两名观察者进行盲法分割。采集后的处理尽量减少，但进行了强度离散化（固定区间大小为25）。提取了101个影像组学特征（形状n = 12；一阶n = 16；纹理n = 73）。通过Pearson相关性和变异系数（CV）评估每个特征的纵向重复性。还使用组内相关系数（ICC）和Bland-Altman分析对观察者间特征值一致性进行了量化。根据特征变异系数（CV<5%）、ICC（>0.75）以及观察者间差异与观察者间均值的比值δ<5%，确定两台扫描仪上最具重复性的影像组学特征集。
影像组学特征值没有随时间变化的趋势。纵向特征重复性CV在扫描仪A上的范围为0.01 - 38.60%（均值/中位数：12.5%/9.9%），在扫描仪B上为0.01 - 40.47%（8.49%/7.34%）。形状特征的重复性明显优于一阶和纹理特征（所有P<0.01）。在两台扫描仪之间，纹理特征观察到显著的纵向重复性差异（P<0.001），但形状和一阶特征没有（P>0.30）。一阶和纹理特征的观察者间依赖性变异小于采集依赖性变异。它们在两台扫描仪上也显示出良好的观察者间一致性（A：ICC = 0.80±0.23；B：ICC = 0.80±0.22），与采集重复性无关。两台扫描仪上共同的可重复影像组学特征，包括12个形状特征、0个一阶特征和3个纹理特征，被确定为最具重复性的MRI影像组学特征集。
在这项采用3D T1W TSE采集的体模研究中，影像组学特征表现出异质性的纵向重复性，而形状特征是最具重复性的。本研究中得出的最具重复性的影像组学特征集应有助于在未来临床应用中选择可靠的影像组学特征。
