Co-registration of stereotactic MRI and isofieldlines during deep brain stimulation.
OBJECTIVE
The parameter adjustment process during deep brain stimulation (DBS) for dystonia remains time consuming and based on clinical observation alone. The aim was to correlate the electric field with the GPi anatomy to be able to study the stimulated volume.


METHODS
We developed a computer-assisted method (model) for visualizing electric field in reference to the stereotactic space. Electric field values were correlated with the GPi anatomy (stereotactic Magnetic Resonance Imaging) in one reference patient.


RESULTS
Using this methodology it becomes possible to correlate the electric field distributions for patient specific parameters with the anatomical information. The application to one patient showed that the 0.1V/mm isofieldline fits best with the lateral GPi borders at the level of the stimulated contacts.


CONCLUSIONS
The electric field is a crucial parameter as it is assumed to be responsible for triggering action potentials. Electric field visualisation allows the calculation of the stimulated volume for a given isoline. Its application to our whole patient population might help in determining a threshold for obtaining a therapeutic effect, to date unknown, and consequently in optimizing the parameter setting in each patient.
Hemm
Simone
S
Department of Neurosurgery, Research Group on Movement Disorders, University Hospital, Montpellier, France.
Mennessier
Gérard
G
Vayssière
Nathalie
N
Cif
Laura
L
Coubes
Philippe
P
D001921:Brain / Q000033:anatomy & histology; D001931:Brain Mapping; D003198:Computer Simulation; D046690:Deep Brain Stimulation; D004421:Dystonia / Q000473:pathology* / Q000628:therapy*; D004574:Electromagnetic Fields; D006801:Humans; D008279:Magnetic Resonance Imaging; D013238:Stereotaxic Techniques