Computer-assisted transcranial magnetic stimulation

(neurology::therapy)

TMS has been proven to be useful as therapy for neurological disorders but it is still unknown what the impact is of TMS upon the neurophysiology. We developed a powerful numerical technique, i.e. independent impedance method [4] that can be employed in a patient-specific way for calculating the eddy currents in a three-dimensional volumetric conductor model. Moreover, we are able to calculate the eddy currents when incorporating anisotropic conductivity values using diffusion tensor imaging (DTI). We focus at understanding in a more correct way what the impact is of TMS and in developing more optimized coil configurations so to develop a more accurate therapy assisted with computer models. 

Realistic head model with calculation of induced eddy currents with the inclusion of anisotropy using DTI. First row shows the anatomical volume conductor model, second row shows the difference between the induced currents using anisotropy and the induced currents using isotropy, third row shows the percentual difference between the induced currents with incorporation of anisotropy and without anisotropic conductivities.


[4] N. De Geeter, G. Crevecoeur, L. Dupré, "An Efficient 3-D Eddy-Current Solver Using an Independent Impedance Method for Transcranial Magnetic Stimulation," IEEE Trans. Biomed. Eng., vol. 58, no. 2, pp. 310-320, feb 2011.