PURPOSE The reproducibility of neurite orientation dispersion and density imaging (NODDI) metrics in the human brain has not been explored across different magnetic resonance (MR) scanners from different vendors. This study aimed to evaluate the scan-rescan and inter-vendor reproducibility of NODDI metrics in white and gray matter of healthy subjects using two 3-T MR scanners from two vendors. METHODS Ten healthy subjects (7 males; mean age 30 ± 7 years, range 23-37 years) were included in the study. Whole-brain diffusion-weighted imaging was performed with b-values of 1000 and 2000 s/mm2 using two 3-T MR scanners from two different vendors. Automatic extraction of the region of interest was performed to obtain NODDI metrics for whole and localized areas of white and gray matter. The coefficient of variation (CoV) and intraclass correlation coefficient (ICC) were calculated to assess the scan-rescan and inter-vendor reproducibilities of NODDI metrics. RESULTS The scan-rescan and inter-vendor reproducibility of NODDI metrics (intracellular volume fraction and orientation dispersion index) were comparable with those of diffusion tensor imaging (DTI) metrics. However, the inter-vendor reproducibilities of NODDI (CoV = 2.3-14%) were lower than the scan-rescan reproducibility (CoV: scanner A = 0.8-3.8%; scanner B = 0.8-2.6%). Compared with the finding of DTI metrics, the reproducibility of NODDI metrics was lower in white matter and higher in gray matter. CONCLUSION The lower inter-vendor reproducibility of NODDI in some brain regions indicates that data acquired from different MRI scanners should be carefully interpreted.

中文翻译：

---

神经突取向分散和密度成像指标的扫描-重新扫描和供应商间可重复性。

目的尚未在来自不同供应商的不同磁共振（MR）扫描仪上探索人脑中神经突取向分散和密度成像（NODDI）指标的可重复性。这项研究的目的是使用来自两个供应商的两个3-T MR扫描仪评估健康受试者的白色和灰色物质中NODDI指标的扫描-重新扫描和供应商间可重复性。方法本研究包括10名健康受试者（7名男性；平均年龄30±7岁，范围23-37岁）。使用来自两个不同供应商的两个3-T MR扫描仪，以b值分别为1000和2000 s / mm2进行全脑扩散加权成像。执行感兴趣区域的自动提取以获得白和灰质整个区域和局部区域的NODDI度量。计算变异系数（CoV）和组内相关系数（ICC）以评估NODDI指标的扫描-再扫描和供应商间可重复性。结果NODDI指标（细胞内体积分数和取向分散指数）的扫描-再扫描和供应商间再现性与扩散张量成像（DTI）指标相当。但是，NODDI的供应商间可重复性（CoV = 2.3-14％）低于扫描-再扫描可重复性（CoV：扫描仪A = 0.8-3.8％；扫描仪B = 0.8-2.6％）。与DTI度量相比，NODDI度量的可重复性在白质中较低，在灰质中较高。结论在某些大脑区域，NODDI的供应商间可重复性较低，这表明应仔细解释从不同MRI扫描仪获得的数据。