This work aimed at assessing the reliability of intravoxel incoherent motion (IVIM) parameters sensitive to perfusion changes in the cervical cord by determining the test-retest variability across subjects and different post-processing fitting algorithms. IVIM test-retest scans were acquired in the cervical cord (C1-C3) of 10 healthy subjects on a 3T MRI scanner, with a 15-minute break in-between. IVIM parameters, including microvascular volume fraction (F), pseudo-diffusion coefficient (D*), blood flow-related coefficient (F · D*), and diffusion coefficient (D), were derived using voxel-wise and region of interest (ROI)-wise fits. The reliability of each IVIM parameter was determined with coefficients of variation (CV), intraclass correlation coefficients (ICC), Bland-Altman analysis and linear regression. To assess the effects of the different fitting approaches, a two-way repeated-measures analysis of variance (ANOVA) was conducted on the CVs calculated across fitting algorithms. Mean CVs of IVIM parameters calculated across subjects using the voxel-wise fit was lower in the white matter (WM) and grey matter (GM) (2.6% to 15.6%; 2.2% to 16.4%, respectively) compared with those calculated using the ROI-wise fit approach (WM: 4.5%-32.2%; GM: 3.4%-53.4%). The voxel-wise fit in the WM yielded higher ICC values (good-to-excellent, 0.71 – 0.97) compared to the ROI-wise fit approach (0.49 – 0.90). IVIM parameters, derived using the voxel-wise fitting approach, demonstrated a high reliability in the cervical cord. Robust IVIM metrics, observed across scans and subjects, can facilitate studies targeting perfusion impairment and pave the way to future clinical trials assessing perfusion impairment as a potential quantitative biomarker.

中文翻译：

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颈髓体素内不相干运动 (IVIM) 测量的重测重复性

这项工作旨在通过确定受试者之间的重测变异性和不同的后处理拟合算法，评估对颈髓灌注变化敏感的体素内不相干运动（IVIM）参数的可靠性。使用 3T MRI 扫描仪对 10 名健康受试者的颈髓 (C1-C3) 进行 IVIM 重测扫描，中间休息 15 分钟。 IVIM 参数，包括微血管体积分数 ( F )、伪扩散系数 ( D* )、血流相关系数 ( F · D* ) 和扩散系数 ( D )，是使用体素方式和感兴趣区域导出的 ( ROI）明智的适合。每个 IVIM 参数的可靠性通过变异系数 (CV)、组内相关系数 (ICC)、Bland-Altman 分析和线性回归来确定。为了评估不同拟合方法的效果，对跨拟合算法计算的 CV 进行了双向重复测量方差分析 (ANOVA)。与使用体素拟合计算出的 IVIM 参数的平均 CV 相比，在白质 (WM) 和灰质 (GM) 中计算出的 IVIM 参数的平均 CV 较低（分别为 2.6% 至 15.6%；2.2% 至 16.4%）。 ROI-wise 拟合方法（WM：4.5%-32.2%；GM：3.4%-53.4%）。与 ROI 拟合方法 (0.49 – 0.90) 相比，WM 中的体素拟合产生了更高的 ICC 值（良好到优秀，0.71 – 0.97）。使用体素拟合方法导出的 IVIM 参数在颈髓中表现出高可靠性。在扫描和受试者中观察到的稳健的 IVIM 指标可以促进针对灌注损伤的研究，并为未来评估灌注损伤作为潜在定量生物标志物的临床试验铺平道路。