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Proceedings Paper

Brain-skull boundary conditions in a computational deformation model
Author(s): Songbai Ji; Fenghong Liu; David Roberts; Alex Hartov; Keith Paulsen
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Paper Abstract

Brain shift poses a significant challenge to accurate image-guided neurosurgery. To this end, finite element (FE) brain models have been developed to estimate brain motion during these procedures. The significance of the brain-skull boundary conditions (BCs) for accurate predictions in these models has been explored in dynamic impact and inertial rotation injury computational simulations where the results have shown that the brain mechanical response is sensitive to the type of BCs applied. We extend the study of brain-skull BCs to quasi-static brain motion simulations which prevail in neurosurgery. Specifically, a frictionless brain-skull BC using a contact penalty method master-slave paradigm is incorporated into our existing deformation forward model (forced displacement method). The initial brain-skull gap (CSF thickness) is assumed to be 2mm for demonstration purposes. The brain surface nodes are assigned as either fixed (at bottom along the gravity direction), free (at brainstem), with prescribed displacement (at craniotomy) or as slave nodes potentially in contact with the skull (all the remaining). Each slave node is assigned a penalty parameter (β=5) such that when the node penetrates the rigid body skull inner-surface (master surface), a contact force is introduced proportionally to the penetration. Effectively, brain surface nodes are allowed to move towards or away from the cranium wall, but are ultimately restricted from penetrating the skull. We show that this scheme improves the model's ability to represent the brain-skull interface.

Paper Details

Date Published: 22 March 2007
PDF: 11 pages
Proc. SPIE 6509, Medical Imaging 2007: Visualization and Image-Guided Procedures, 65092J (22 March 2007); doi: 10.1117/12.709641
Show Author Affiliations
Songbai Ji, Dartmouth College (United States)
Fenghong Liu, Dartmouth College (United States)
David Roberts, Dartmouth-Hitchcock Medical Ctr. (United States)
Norris Cotton Cancer Ctr. (United States)
Alex Hartov, Dartmouth College (United States)
Norris Cotton Cancer Ctr. (United States)
Keith Paulsen, Dartmouth College (United States)
Norris Cotton Cancer Ctr. (United States)


Published in SPIE Proceedings Vol. 6509:
Medical Imaging 2007: Visualization and Image-Guided Procedures
Kevin R. Cleary; Michael I. Miga, Editor(s)

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