Prajapati Harshkumar S, Merchant-Borna Kian, Bazarian Jeffrey J, Linte Cristian A, Cahill Nathan D
Center for Imaging Science, Rochester Institute of Technology, Rochester, NY, USA.
Emergency Medicine Research, University of Rochester Medical Center, Rochester, NY, USA.
Proc SPIE Int Soc Opt Eng. 2022 Feb-Mar;12036. doi: 10.1117/12.2613105. Epub 2022 Apr 4.
Accurate alignment of longitudinal diffusion weighted imaging (DWI) scans of a subject is necessary to investigate longitudinal changes in DWI-derived diffusion measures such as fractional anisotropy (FA), mean diffusivity (MD), and quantitative anisotropy (QA). Currently, studies investigating these changes in the context of repetitive non-concussive head injuries (RHIs) perform pairwise rigid registration of all scans of a subject to the first scan or any other reference scan or template. Prajapati . show that this strategy of performing pairwise rigid registration lead to a discrepancy in the rigid transformations. To eliminate this discrepancy, they propose performing transitive inverse consistent rigid registration of the longitudinal scans, and they analyze the impact of this approach on the mean values of the local/regional estimates of these diffusion measures. In this work, we further analyze the impact of transitive inverse consistent rigid registration on the distributions (CDFs) of the local/regional estimates of diffusion measures. We identify the regions (among the 48 anatomically defined regions by the JHU DTI-based white matter atlas) that show significant differences in the CDFs obtained using pairwise inverse consistent and transitive inverse consistent rigid registration by performing the two sided Kolmogorov-Smirnov(KS) hypothesis test. We find that for MD and QA, there are certain subjects that have five or more regions with significant differences in the CDFs. Further, these are the same subjects for which Prajapati . found regions with 2%-4% differences in the mean values of these diffusion measures. Thus, our results further strengthen the recommendation made by Prajapati . to employ transitive inverse consistent rigid registration when investigating local/regional longitudinal changes in diffusion measures.
为了研究扩散加权成像（DWI）衍生的扩散测量指标（如分数各向异性（FA）、平均扩散率（MD）和定量各向异性（QA））的纵向变化，对受试者的纵向DWI扫描进行精确对齐是必要的。目前，在重复性非脑震荡性头部损伤（RHI）背景下研究这些变化的研究，是将受试者的所有扫描与第一次扫描或任何其他参考扫描或模板进行成对刚性配准。Prajapati等人表明，这种成对刚性配准策略会导致刚性变换中的差异。为了消除这种差异，他们建议对纵向扫描进行传递性逆一致刚性配准，并分析这种方法对这些扩散测量指标的局部/区域估计平均值的影响。在这项工作中，我们进一步分析传递性逆一致刚性配准对扩散测量指标局部/区域估计分布（CDF）的影响。通过进行双侧柯尔莫哥洛夫-斯米尔诺夫（KS）假设检验，我们确定了（在基于约翰霍普金斯大学DTI的白质图谱定义的48个解剖区域中）那些在使用成对逆一致和传递性逆一致刚性配准获得的CDF中显示出显著差异的区域。我们发现，对于MD和QA，某些受试者有五个或更多区域的CDF存在显著差异。此外，这些受试者与Prajapati等人发现这些扩散测量指标平均值有2%-4%差异的受试者相同。因此，我们的结果进一步强化了Prajapati等人提出的建议，即在研究扩散测量指标的局部/区域纵向变化时采用传递性逆一致刚性配准。
