# A Workflow for Creating Gastric Computational Models from SPARC Scaffolds
## 4 Discussion  
The SPARC program has developed a number organ scaffolds (e.g., heart, lung, stomach, intestine, colon) from various species (e.g., mouse, rat, cat, sheep, pig, human) that are publicly available in the SPARC portal ([[https://sparc.science/data](https://sparc.science/data)]([https://sparc.science/data](https://sparc.science/data))). However, these scaffolds require additional processing to be useable in simulations. In this study, a workflow was developed to create computational FEM models from the SPARC scaffold of the rat stomach [27]. Figure 5: Overlaid signal traces of cellular activation in the three computational models for nine different points (**A–I**) on the stomach. While the solution for the two 3D models had almost identical activation at these nine points, the solution for the 2D surface model showed small deviations in activation times from the 3D simulations. The green star indicates the location of the pacemaker region. The approximate location of the lower esophageal sphincter (LES) is identified with an arrow. Figure 6: Activation time map of the three computational models for one full slow wave cycle. While the activation and propagation profiles of the two 3D models were almost identical, the activation time difference between 2D surface model and the 3D models was as high as 1 s at the most distal stomach. The approximate location of the lower esophageal sphincter (LES) is identified with an arrow. The FEM models of the rat stomach have several potential applications. They will be primarily used to enhance our understanding of gastric electrophysiology and to investigate the optimal pacing and stimulation parameters in electrical therapies [38; 39]. In addition, contractile activity in the stomach and its relationship with slow waves can be modelled using coupled electro-mechanical simulations [11; 12; 40]. Experimentally informed muscle layer representation and fiber orientations in our models would improve the accuracy in modelling the strength and coordination of the motor patterns in the stomach. These improved motor patterns can further inform mixing of luminal contents and flow patterns in the stomach via computational fluid dynamics simulations [41; 42]. These simulations can be also used for the investigation of the breakdown of ingested foods [43] and drug delivery [44; 45]. Since SPARC scaffolds generally share similar topology and mesh characteristics across organs, our developed workflow can be readily applied to other SPARC scaffolds to generate computational FEM models informed by subject-specific anatomical data. For instance, the uterus shares similar smooth muscle layers and fiber characteristics with the stomach (e.g., longitudinal and circular muscles), and our workflow could be adapted to study uterine functions [46; 47]. The three FEM models of the rat stomach created in this study had different levels of complexity incorporated from experimental measurements of the gastric wall thickness and fiber orientations in longitudinal and circular muscle layers reported in [14]. Integrating the properties of the gut musculature to the FEM models was a significant advancement to the rat stomach scaffold. The developed computational models that have been made publicly available can now be used to investigate complex and interacting mechanisms regulating gastric motility and the structure-function relationship in the stomach. In addition, these models can be used to assess the efficacy of a vast range of parameters in electrical therapies more accurately and thus to fine-tune the protocols, with each model offering different benefits and limitations, making them suitable for various applications. The level of refinement in each developed model was determined by convergence in whole-organ electrophysiological simulations. A greater number of solution points and much smaller elements were required in the 3D volume models, mainly due to very thin muscle layers in the stomach.