Assessment of a method to determine deep brain stimulation targets using deterministic tractography in a navigation system

Abstract

Recent advances in imaging permit radiologic identification of target structures for deep brain stimulation (DBS) for movement disorders. However, these methods cannot detect the internal subdivision and thus cannot determine the appropriate DBS target located within those subdivisions. The aim of this study is to provide a straightforward method to obtain an optimized target (OT) within DBS target nuclei using a widely available navigation system. We used T1- and T2-weighted images, fluid-attenuated inversion recovery (FLAIR) sequence, and diffusion tensor imaging (DTI) of nine patients operated for DBS in our center. Using the StealthViz® software, we segmented the targeted deep structures (subcortical targets) and the anatomically identifiable areas to which these target nuclei were connected (projection areas). We generated fiber tracts from the projection areas. By identifying their intersections with the subcortical targets, we obtained an OT within the DBS target nuclei. We computed the distances from the clinically effective electrode contacts (CEEC) to the OT obtained by our method and the targets provided by the atlas. These distances were compared using a Wilcoxon signed-rank test, with p < 0.05 considered statistically significant. We were able to identify OT coincident with the motor part of the subthalamic nucleus and the ventral intermediate nucleus. We clinically tested the results and found that the CEEC were significantly more closely related to the OT than with the targets obtained by the atlas. Our present results show that this novel method permits optimization of the stimulation site within the internal subdivisions of target nuclei for DBS.

Individualized parcellation of the subthalamic nucleus in patients with Parkinson's disease with 7T MRI

“…This arrangement was also observed in another 3 T functional and structural connectivity study based on averaged data of healthy subjects, but could not be demonstrated consistently in all individual subjects (Brunenberg et al, 2012). Finally the STN’s connectivity was previously investigated in PD patients as well, although this only concerned its motor area and analyses were only performed in a qualitative manner (Avecillas-Chasin et al, 2015). Here, we show that the three zones can also be objectively and quantitatively identified in patients with PD and, importantly, on an individual basis.…”

Worsening of Verbal Fluency After Deep Brain Stimulation in Parkinson's Disease: A Focused Review

“…Such diffusion-based tractography has already been used to examine the tissue and pathways targeted in DBS treatment [6], [49]. These advanced techniques allow for detailed delineation of the connections between the STN (and GPi), cortex and other basal ganglia structures at the individual patient level.…”

Using probabilistic tractography to target the subcallosal cingulate cortex in patients with treatment resistant depression

“…Regarding the tractography methods, previous methods are based on iterative deterministic assessments, which is prone to sampling limitations (Avecillas-Chasin et al, 2015; Choi et al, 2015). While the probabilistic approach is time intensive, the data-driven nature may be more practical and provide advantages over a manual iterative approach.…”