OBJECTIVEDeep brain stimulation (DBS) is an effective procedure in improving motor symptoms for patients with advanced Parkinson’s disease (PD) through the use of high-frequency stimulation. Although one of the most commonly used target sites for DBS, sensorimotor regions of the globus pallidus interna (GPi) have yet to be thoroughly described with advanced neuroimaging analysis in vivo for human subjects. Furthermore, many imaging studies to date have been performed in a research setting and bring into question the feasibility of their applications in a clinical setting, such as for surgical planning. This study compares two different tractography methods applied to clinically feasible acquisition sequences in identifying sensorimotor regions of the GPi and the subthalamic nucleus (STN) in patients with advanced PD selected to undergo DBS.METHODSSeven patients with refractory PD selected for DBS were examined by MRI. Diffusion images were acquired with an average acquisition time of 15 minutes. Probabilistic and deterministic tractography methods were applied to each diffusion-weighted data set using FSL and MRtrix, respectively. Fiber assignment was performed using combined sensorimotor areas as initiation seeds and the STN and GPi, separately, as inclusion masks. Corticospinal tracts were excluded by setting the cerebral peduncles as exclusion masks. Variability between proposed techniques was shown using center of gravity (CoG) coordinates.RESULTSDeterministic and probabilistic corticopallidal and corticosubthalamic pathways were successfully reconstructed for all subjects across all target sites (bilaterally). Both techniques displayed large connections between the sensorimotor cortex with the posterolateral aspect of the ipsilateral GPi and the posterosuperolateral aspect of the ipsilateral STN. The average variability was 2.67 mm, with the probabilistic method identifying the CoG consistently more posterior and more lateral than the deterministic method.CONCLUSIONSSuccessful delineation of the sensorimotor regions in both the GPi and STN is achievable within a clinically reasonable timeframe. The techniques described in this paper may enhance presurgical planning with increased accuracy and improvement of patient outcomes in patients undergoing DBS. The variability found between tracking techniques warrants the use of the probabilistic tractography method over the deterministic method for presurgical planning. Probabilistic tractography was found to have an advantage over deterministic tractography in its sensitivity, in accurately describing previously described tracts, and in its ability to detect a larger number of fibers.

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The goal of glioma surgery is maximal safe resection in order to provide optimal tumor control and survival benefit to the patient. There are multiple imaging modalities beyond traditional contrast-enhanced magnetic resonance imaging (MRI) that have been incorporated into the preoperative workup of patients presenting with gliomas. The aim of these imaging modalities is to identify cortical and subcortical areas of eloquence, and their relationship to the lesion. In this article, multiple modalities are described with an emphasis on the underlying technology, clinical utilization, advantages, and disadvantages of each. functional MRI and its role in identifying hemispheric dominance and areas of language and motor are discussed. The nuances of magnetoencephalography and transcranial magnetic stimulation in localization of eloquent cortex are examined, as well as the role of diffusion tensor imaging in defining normal white matter tracts in glioma surgery. Lastly, we highlight the role of stimulated Raman spectroscopy in intraoperative histopathological diagnosis of tissue to guide tumor resection. Tumors may shift the normal arrangement of functional anatomy in the brain; thus, utilization of multiple modalities may be helpful in operative planning and patient counseling for successful surgery.

<b><i>Introduction:</i></b> Magnetic resonance-guided focused ultrasound (MRgFUS) represents an incisionless treatment option for essential or parkinsonian tremor. The incisionless nature of this procedure has garnered interest from both patients and providers. As such, an increasing number of centers are initiating new MRgFUS programs, necessitating development of unique workflows to optimize patient care and safety. Herein, we describe establishment of a multi-disciplinary team, workflow processes, and outcomes for a new MRgFUS program. <b><i>Methods:</i></b> This is a single-academic center retrospective review of 116 consecutive patients treated for hand tremor between 2020 and 2022. MRgFUS team members, treatment workflow, and treatment logistics were reviewed and categorized. Tremor severity and adverse events were evaluated at baseline, 3, 6, and 12 months post-MRgFUS with the Clinical Rating Scale for Tremor Part B (CRST-B). Trends in outcome and treatment parameters over time were assessed. Workflow and technical modifications were noted. <b><i>Results:</i></b> The procedure, workflow, and team members remained consistent throughout all treatments. Technique modifications were attempted to reduce adverse events. A significant reduction in CRST-B score was achieved at 3 months (84.5%), 6 months (79.8%), and 12 months (72.2%) post-procedure (<i>p</i> &#x3c; 0.0001). The most common post-procedure adverse events in the acute period (&#x3c;1 day) were gait imbalance (61.1%), fatigue and/or lethargy (25.0%), dysarthria (23.2%), headache (20.4%), and lip/hand paresthesia (13.9%). By 12 months, the majority of adverse events had resolved with a residual 17.8% reporting gait imbalance, 2.2% dysarthria, and 8.9% lip/hand paresthesia. No significant trends in treatment parameters were found. <b><i>Conclusions:</i></b> We demonstrate the feasibility of establishing an MRgFUS program with a relatively rapid increase in evaluation and treatment of patients while maintaining high standards of safety and quality. While efficacious and durable, adverse events occur and can be permanent in MRgFUS.

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