BACKGROUND Our study aims to reveal whether the low b-values distribution, high b-values upper limit, and the number of excitation (NEX) influence the accuracy of the intravoxel incoherent motion (IVIM) parameter derived from multi-b-value diffusion-weighted imaging (DWI) in the brain. METHODS This prospective study was approved by the local Ethics Committee and informed consent was obtained from each participant. The five consecutive multi-b DWI with different b-value protocols (0-3500 s/mm2) were performed in 22 male healthy volunteers on a 3.0-T MRI system. The IVIM parameters from normal white matter (WM) and gray matter (GM) including slow diffusion coefficient (D), fast perfusion coefficient (D*) and perfusion fraction (f) were compared for differences among defined groups with different IVIM protocols by one-way ANOVA. RESULTS The D* and f value of WM or GM in groups with less low b-values distribution (less than or equal to 5 b-values) were significantly lower than ones in any other group with more low b-values distribution (all P <  0.05), but no significant differences among groups with more low b-values distribution (P > 0.05). In addition, no significant differences in the D, D* and f value of WM or GM were found between group with one and more NEX of low b-values distribution (all P > 0.05). IVIM parameters in normal WM and GM strongly depended on the choice of the high b-value upper limit. CONCLUSIONS Metrics of IVIM parameters can be affected by low and high b value distribution. Eight low b-values distribution with high b-value upper limit of 800-1000 s/mm2 may be the relatively proper set when performing brain IVIM studies.

中文翻译：

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b值的高低分布会影响正常大脑中从IVIM DWI导出的伪扩散参数吗？

背景技术我们的研究旨在揭示低b值分布，高b值上限以及激励次数（NEX）是否会影响源自多b值扩散的体素不相干运动（IVIM）参数的准确性。大脑中的加权成像（DWI）。方法这项前瞻性研究已获得当地伦理委员会的批准，并获得了每个参与者的知情同意。在3.0-T MRI系统上，对22位男性健康志愿者进行了连续5次具有不同b值协议（0-3500 s / mm2）的多b DWI。比较正常白质（WM）和灰质（GM）的IVIM参数（包括慢扩散系数（D），快速灌注系数（D *）和灌注分数（f）），以比较使用不同IVIM方案的定义组之间的差异方差分析。结果b值较低的组（小于或等于5个b值）的WM或GM的D *和f值显着低于b值较低的其他组（所有P <0.05），但b值分布较低的组之间无显着差异（P> 0.05）。此外，在具有低b值分布的一个或多个NEX的组之间，在WM或GM的D，D *和f值上没有发现显着差异（所有P> 0.05）。正常WM和GM中的IVIM参数强烈取决于高b值上限的选择。结论IVIM参数的度量标准可能受到b值的高低分布的影响。当进行大脑IVIM研究时，八个b值较低的高b值分布上限为800-1000 s / mm2可能是相对合适的设置。