Centre for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), School of Computing, University of Leeds, Leeds, UK; Biomedical Imaging Science Department, Leeds Institute for Cardiovascular and Metabolic Medicine (LICAMM), School of Medicine, University of Leeds, Leeds, UK.
Centre for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), School of Computing, University of Leeds, Leeds, UK; Biomedical Imaging Science Department, Leeds Institute for Cardiovascular and Metabolic Medicine (LICAMM), School of Medicine, University of Leeds, Leeds, UK.
Med Image Anal. 2022 Nov;82:102592. doi: 10.1016/j.media.2022.102592. Epub 2022 Sep 3.
In silico tissue models (viz. numerical phantoms) provide a mechanism for evaluating quantitative models of magnetic resonance imaging. This includes the validation and sensitivity analysis of imaging biomarkers and tissue microstructure parameters. This study proposes a novel method to generate a realistic numerical phantom of myocardial microstructure. The proposed method extends previous studies by accounting for the variability of the cardiomyocyte shape, water exchange between the cardiomyocytes (intercalated discs), disorder class of myocardial microstructure, and four sheetlet orientations. In the first stage of the method, cardiomyocytes and sheetlets are generated by considering the shape variability and intercalated discs in cardiomyocyte-cardiomyocyte connections. Sheetlets are then aggregated and oriented in the directions of interest. The morphometric study demonstrates no significant difference (p>0.01) between the distribution of volume, length, and primary and secondary axes of the numerical and real (literature) cardiomyocyte data. Moreover, structural correlation analysis validates that the in-silico tissue is in the same class of disorderliness as the real tissue. Additionally, the absolute angle differences between the simulated helical angle (HA) and input HA (reference value) of the cardiomyocytes (4.3°±3.1°) demonstrate a good agreement with the absolute angle difference between the measured HA using experimental cardiac diffusion tensor imaging (cDTI) and histology (reference value) reported by (Holmes et al., 2000) (3.7°±6.4°) and (Scollan et al. 1998) (4.9°±14.6°). Furthermore, the angular distance between eigenvectors and sheetlet angles of the input and simulated cDTI is much smaller than those between measured angles using structural tensor imaging (as a gold standard) and experimental cDTI. Combined with the qualitative results, these results confirm that the proposed method can generate richer numerical phantoms for the myocardium than previous studies.
计算机组织模型（即数值体模）为评估磁共振成像的定量模型提供了一种机制。这包括对成像生物标志物和组织微观结构参数进行验证和灵敏度分析。本研究提出了一种生成心肌微观结构真实数值体模的新方法。该方法通过考虑心肌细胞形状的可变性、心肌细胞之间的水交换（闰盘）、心肌微观结构的紊乱程度以及四个薄片的方向，扩展了以前的研究。在该方法的第一阶段，通过考虑心肌细胞形状的可变性和心肌细胞之间的闰盘来生成心肌细胞和薄片。然后将薄片聚集并定向到感兴趣的方向。形态学研究表明，数值和真实（文献）心肌细胞数据的体积、长度和主、次轴分布之间没有显著差异（p>0.01）。此外，结构相关性分析验证了计算机组织与真实组织具有相同的紊乱程度。此外，心肌细胞模拟螺旋角（HA）与输入 HA（参考值）之间的绝对角度差异（4.3°±3.1°）与使用实验心脏扩散张量成像（cDTI）和组织学（参考值）测量的 HA（Holmes 等人，2000 年）之间的绝对角度差异（3.7°±6.4°）和（Scollan 等人，1998 年）（4.9°±14.6°）有很好的一致性。此外，本征向量与输入和模拟 cDTI 薄片角度之间的角度距离远小于使用结构张量成像（作为金标准）和实验 cDTI 测量角度之间的角度距离。结合定性结果，这些结果证实，与以前的研究相比，该方法可以为心肌生成更丰富的数值体模。
