Deep Brain Stimulation Investigated as Brain Injury Treatment
Research Presented at the SFN 2017 Conference
Deep brain stimulation (DBS) in the central thalamus is currently undergoing clinical investigation for the treatment of cognitive impairments due to traumatic brain injury (TBI). The proposed target for this therapy is a fiber pathway in the ascending arousal network which projects through the central thalamus and into the frontal cortex. In order to target this fiber pathway, diffusion tensor imaging (DTI) is acquired along with structural imaging to reconstruct patient-specific fiber tracts. However, DTI acquisitions are susceptible to inaccuracies due to field distortions and the choice of diffusion gradient directions. The goal of this study was to compare fiber tractography results after varying three parameters: 1) the amount of diffusion weighting during acquisition (b-value), 2) the number of acquired diffusion directions, and 3) the correction of distortion introduced by eddy currents and phase encoding. We found that increasing the number of diffusion gradients increased the number of distinct fiber pathways that can be reconstructed, thereby allowing us to identify our proposed target with more confidence. In addition, distortion correction has a major impact on the location of fiber pathways relative to structural anatomy (Figure 1). The tractography results also show that more pathways were reconstructed and were less diffuse with the distortion corrected versus the uncorrected acquisitions. We anticipate that this study will provide guidance on the choice of appropriate DTI acquisition parameters and tractography analyses for patient-specific DBS surgical planning to treat TBI cognitive impairments.