Annu Int Conf IEEE Eng Med Biol Soc. 2021 Nov;2021:4234-4237. doi: 10.1109/EMBC46164.2021.9630644.
Routine diagnosis of gastric motility disorders represents a significant problem to current clinical practice. The non-invasive electrogastrogram (EGG) and magnetogastrogram (MGG) enable the assessment of gastric slow wave (SW) dysrhythmias that are associated with motility disorders. However, both modalities lack standardized methods for reliably detecting patterns of SW activity. Subject-specific anatomical information relating to the geometry of the stomach and its position within the torso have the potential to aid the development of relations between SWs and far-fields. In this study, we demonstrated the feasibility of using magnetic source localization to reconstruct the geometry of an anatomically realistic 3D stomach model. The magnetic fields produced by a small (6.35 × 6.35 mm) N35 neodymium magnet sequentially positioned at 64 positions were recorded by an array of 27 magnetometers. Finally, the magnetic dipole approximation and a particle swarm optimizer were used to estimate the position and orientation of the permanent magnet. Median position and orientation errors of 3.8 mm and 7.3° were achieved. The estimated positions were used to construct a surface mesh, and the Hausdorff Distance and Average Hausdorff Distance dissimilarity metrics for the reconstructed and ground-truth models were 11.6 mm and 2.4 mm, respectively. The results indicate that source localization using the magnetic dipole model can successfully reconstruct the geometry of the stomach.
常规诊断胃动力障碍是当前临床实践中的一个重大问题。非侵入性的胃电图（EGG）和胃磁图（MGG）使我们能够评估与运动障碍相关的胃慢波（SW）节律紊乱。然而，这两种方法都缺乏可靠检测 SW 活动模式的标准化方法。与胃的几何形状及其在躯干内位置有关的特定于主体的解剖学信息，有可能有助于 SW 与远场之间关系的发展。在本研究中，我们展示了使用磁源定位来重建解剖学上逼真的 3D 胃模型的几何形状的可行性。通过一个由 27 个磁力计组成的阵列记录了一个小（6.35×6.35 毫米）N35 钕磁铁依次定位在 64 个位置时产生的磁场。最后，使用磁偶极子近似和粒子群优化器来估计永磁体的位置和方向。实现了 3.8 毫米的中值位置误差和 7.3°的中值方向误差。使用估计的位置构建了一个表面网格，重建模型和真实模型的 Hausdorff 距离和平均 Hausdorff 距离差异度量分别为 11.6 毫米和 2.4 毫米。结果表明，使用磁偶极子模型的源定位可以成功地重建胃的几何形状。
