Image guidance methods in deep brain stimulation

Deep Brain Stimulation (DBS) has shown promise as an alternative therapy for medication refractory neurological disorders (such as Parkinson's disease, essential tremor, and dystonia). DBS requires millimeter accuracy in the targeting of specific deep brain structures. Unfortunately, standard imaging methods (CT, T1 and T2-weighted MRI) have not previously shown significant anatomic contrast of structures that are targeted in DBS. In order to enhance surgical targeting in DBS, we have developed several tools to aid in both indirect and direct targeting of subcortical brain regions. The tools that we have created include the application of a deformable brain atlas, a novel MRI scan (the Fast Gray Matter Acquisition T1 Inversion Recovery, FGATIR) for differentiation of subcortical structures, application of diffusion tractography for localization of functional subregions of the brain, and a complete clinical platform to provide image guidance integrating all the tools mentioned previously.;The methods developed in this work were evaluated to determine their potential clinical utility. The FGATIR scan was found to have enhanced contrast of three of the most common structures targeted for DBS versus standard scans. To determine potential targeting advantages of the FGATIR scan, a study was conducted that compared different targeting methods on the STN. This study revealed that targeting using the FGATIR was not significantly better than more basic methods of targeting for the specific target studied, the STN. A potential reason that more advanced imaging methods are not significantly more useful is that the STN is a target that may be consistently targeted based off known distances from landmarks alone. A study was conducted to compare probabilistic diffusion tractography (PDT) delineated regions for sensory and motor within the thalamus. These PDT delineated regions showed correlation with sensory and motor atlas and microelectrode data. A software and hardware system was developed that integrated all of these methods (as well as standard imaging methods) into a single multi-modal platform. This system allows for clinical targeting based off of all these methods combined together. The end result of this work is a clinically feasible methodology for multi-modal targeting of DBS integrating multiple novel techniques.