Comparing Isotropic and Anisotropic Brain Conductivity Modeling: Planning Optimal Depth-Electrode Placement in White Matter for Direct Stimulation Therapy in an Epileptic Circuit

L. C. Zaragoza[1], B. Hondorp[2], M. A. Rossi[3]
[1]ITESM, Monterrey, Mexico
[2]Rush Medical College, Chicago, IL, USA
[3]Rush University Medical Center, Chicago, IL, USA

The goal of our work was to calculate a patient-specific brain conductivity map for predicting the extent to which direct stimulation therapy can strategically propagate through pathological white matter. Our laboratory developed isotropic and anisotropic human brain finite element method (FEM) models derived from SPGR magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI), respectively for estimating tissue conductivities during direct stimulation therapy. Specifically, the electrostatic electric field (E-field) and current density surrounding two modeled depth contacts virtually placed in white matter were modeled for a patient with bilaterally independent intractable temporal lobe epileptic sources. The more sophisticated anisotropic model was developed to challenge our three-compartment isotropic model (Rossi et al, 2010).