Development of a Semi-automatic Finite Element Modeling Workflow for the Evaluation of Cranial Suture-Bone Complex Temporal Strain Evolution During Growth.

Purpose: This study aimed to develop a semi-automatic workflow for medical image segmentation and finite element (FE) modeling. The workflow was subsequently used to investigate the temporal evolution of the localized mechanical strain in the rat coronal suture during normal growth.

Methods: The subject-specific FE models were created based on in vivo longitudinal micro-computed tomography images acquired from n = 4 rats (AUP00003759, 11/04/2021). The FE models were created through a semi-automatic workflow that consisted of a semi-automatic segmentation of the rat cranial sutures, a simplified full skull model, and the detailed coronal suture model. Simulated intracranial pressure loading was implemented, and the localized equivalent, maximum principal, and minimum principal strains were estimated at volumes of interest (VOIs) selected along the suture-bone interface.

Results: The semi-automatic segmentations were consistent among operators with a coefficient of variation of 1.8% and showed good agreement compared to the manual segmentation, with maximum differences of 4.1% and 2.0% in terms of suture volume and surface area, respectively. The estimated strains evolved with a trend increasing from 7 to 9 week and 9 to 11 week time intervals and decreasing from 11 to 16 week time interval for all VOIs. The results showed that strains at VOIs significantly changed (p < 0.05) over time. The concave regions of the suture experienced the highest magnitude of strains.

Conclusion: The presented research has developed an appropriate semi-automatic FE workflow capable of evaluating temporal changes in mechanical strain of cranial sutures during growth, and was utilized to demonstrate transient and location-specific changes in the rat coronal suture.