PURPOSE To assess intrascanner repeatability and cross-scanner comparability for diffusion tensor imaging (DTI) metrics in a multicenter clinical trial. METHODS DTI metrics (including longitudinal diffusivity [LD], fractional anisotropy [FA], mean diffusivity [MD], and transverse diffusivity [TD]) from pyramidal tracts for healthy controls were calculated from images acquired on twenty-seven 3T MR scanners (Siemens and GE) with 6 different scanner models and 7 different software versions as part of the NN102/SPRINT-MS clinical trial. Each volunteer underwent two scanning sessions on the same scanner. Signal-to-noise ratio (SNR) and signal-to-noise floor ratio (SNFR) were also assessed. RESULTS DTI metrics showed good scan-rescan repeatability. There were no significant differences between scans and rescans in LD, FA, MD, or TD values. Although the cross-scanner coefficient of variation (CV) values for all DTI metrics were <5.7%, significant differences were observed for LD (p < 3.3e-5) and FA (p < 0.0024) when GE scanners were compared with Siemens scanners. Significant differences were also observed for SNR when comparing GE scanners and Siemens Skyra scanners (p < 1.4e-7) and when comparing Siemens Skyra scanners and TIM Trio scanners (p < 1.0e-10). Analysis of background signal also demonstrated differences between GE and Siemens scanners in terms of signal statistics. The measured signal intensity from a background noise region of interest was significantly higher for GE scanners than for Siemens scanners (p < 1.2e-12). Significant differences were also observed for SNFR when comparing GE scanners and Siemens Skyra scanners (p < 2.5e-11), GE scanners and Siemens Trio scanners (p < 7.5e-11), and Siemens Skyra scanners and TIM Trio scanners (p < 2.5e-9). CONCLUSIONS The good repeatability of the DTI metrics among the 27 scanners used in this study confirms the feasibility of combining DTI data from multiple centers using high angular resolution sequences. Our observations support the feasibility of longitudinal multicenter clinical trials using DTI outcome measures. The noise floor level and SNFR are important parameters that must be assessed when comparing studies that used different scanner models.

中文翻译：

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在SPRINT-MS多中心试验中，对健康受试者的DTI指标进行扫描-再扫描重复性和交叉扫描仪可比性。

目的在多中心临床试验中评估弥散张量成像（DTI）指标的扫描仪内重复性和交叉扫描仪可比性。方法根据在27台3T MR扫描仪（西门子）上采集的图像，计算出健康对照者锥体束的DTI指标（包括纵向扩散率[LD]，分数各向异性[FA]，平均扩散率[MD]和横向扩散率[TD]）。和GE），这是NN102 / SPRINT-MS临床试验的一部分，具有6种不同的扫描仪型号和7种不同的软件版本。每个志愿者在同一台扫描仪上进行了两次扫描。还评估了信噪比（SNR）和信噪底比（SNFR）。结果DTI指标显示良好的扫描-重新扫描可重复性。LD，FA，MD或TD值的扫描与重新扫描之间没有显着差异。尽管所有DTI指标的交叉扫描仪变异系数（CV）值均<5.7％，但当GE扫描仪与西门子扫描仪进行比较时，LD（p <3.3e-5）和FA（p <0.0024）观察到显着差异。比较GE扫描仪和Siemens Skyra扫描仪（p <1.4e-7）以及比较Siemens Skyra扫描仪和TIM Trio扫描仪（p <1.0e-10）时，也观察到SNR的显着差异。对背景信号的分析还证明了GE和Siemens扫描仪在信号统计方面的差异。GE扫描仪从感兴趣的背景噪声区域测得的信号强度显着高于西门子扫描仪（p <1.2e-12）。比较GE扫描仪和Siemens Skyra扫描仪时，SNFR也观察到显着差异（p <2.5e-11），GE扫描仪和Siemens Trio扫描仪（p <7.5e-11）以及Siemens Skyra扫描仪和TIM Trio扫描仪（p <2.5e-9）。结论本研究中使用的27台扫描仪中DTI指标具有良好的可重复性，这证实了使用高角度分辨率序列组合来自多个中心的DTI数据的可行性。我们的观察结果支持使用DTI结果指标进行纵向多中心临床试验的可行性。本底噪声水平和SNFR是比较使用不同扫描仪型号的研究时必须评估的重要参数。结论本研究中使用的27台扫描仪中DTI指标具有良好的可重复性，这证实了使用高角度分辨率序列组合来自多个中心的DTI数据的可行性。我们的观察结果支持使用DTI结果指标进行纵向多中心临床试验的可行性。本底噪声水平和SNFR是比较使用不同扫描仪型号的研究时必须评估的重要参数。结论本研究中使用的27台扫描仪中DTI指标具有良好的可重复性，这证实了使用高角度分辨率序列组合来自多个中心的DTI数据的可行性。我们的观察结果支持使用DTI结果指标进行纵向多中心临床试验的可行性。本底噪声水平和SNFR是比较使用不同扫描仪型号的研究时必须评估的重要参数。