scholarly journals Spatial versus angular resolution for tractography-assisted planning of deep brain stimulation

2019 ◽  
Author(s):  
Luka C. Liebrand ◽  
Guido A. van Wingen ◽  
Frans M. Vos ◽  
Damiaan Denys ◽  
Matthan W.A. Caan
Keyword(s):  
Deep Brain Stimulation ◽  
Spatial Resolution ◽  
Brain Stimulation ◽  
Diffusion Mri ◽  
Angular Resolution ◽  
Internal Capsule ◽  
High Angular Resolution ◽  
Scanning Time ◽  
Mri Protocol ◽  
Deep Brain

AbstractGiven the restricted total scanning time for clinical neuroimaging, it is unclear whether clinical diffusion MRI protocols would benefit more from higher spatial resolution or higher angular resolution. In this work, we investigated the relative benefit of improving spatial or angular resolution in diffusion MRI to separate two parallel running white matter tracts that are targets for deep brain stimulation: the anterior thalamic radiation and the supero-lateral branch of the medial forebrain bundle. Both these tracts are situated in the ventral anterior limb of the internal capsule, and recent studies suggest that targeting a specific tract could improve treatment efficacy. Therefore, we scanned 19 healthy volunteers at 3T and 7T according to three diffusion MRI protocols with respectively standard clinical settings, increased spatial resolution of 1.4 mm, and increased angular resolution (64 additional gradient directions at b=2200s/mm2). We performed probabilistic tractography for all protocols and quantified the separability of both tracts. The higher spatial resolution protocol improved separability by 41% with respect to the clinical standard, presumably due to decreased partial voluming. The higher angular resolution protocol resulted in increased apparent tract volumes and overlap, which is disadvantageous for application in precise treatment planning. We thus recommend to increase the spatial resolution for deep brain stimulation planning to 1.4 mm while maintaining angular resolution. This recommendation complements the general advice to aim for high angular resolution to resolve crossing fibers, confirming that the specific application and anatomical considerations are leading in clinical diffusion MRI protocol optimization.

scholarly journals Toward a unified connectomic target for deep brain stimulation in obsessive-compulsive disorder

2019 ◽  
Author(s):  
Ningfei Li ◽  
Juan Carlos Baldermann ◽  
Astrid Kibleur ◽  
Svenja Treu ◽  
Harith Akram ◽  
...  
Keyword(s):  
Deep Brain Stimulation ◽  
Clinical Improvement ◽  
Obsessive Compulsive Disorder ◽  
Brain Stimulation ◽  
Internal Capsule ◽  
Anterior Cingulate ◽  
Obsessive Compulsive ◽  
Compulsive Disorder ◽  
Fiber Tracts ◽  
Deep Brain

AbstractMultiple surgical targets have been proposed for treating obsessive-compulsive disorder (OCD) with deep brain stimulation (DBS). However, different targets may modulate the same neural network responsible for clinical improvement. Here we analyzed data from four cohorts of OCD patients (N = 50) that underwent DBS to the anterior limb of the internal capsule (ALIC), the nucleus accumbens (NAcc) or the subthalamic nucleus (STN). Fiber tracts that were predominantly connected to electrodes in good or poor DBS responders were isolated from a normative structural connectome and assigned a predictive value. Strikingly, the same fiber bundle was related to treatment response when independently analyzing two large training cohorts that targeted either ALIC or STN. This discriminative tract is a subsection of the ALIC and connects frontal regions (such as the dorsal anterior cingulate, dACC, and ventral prefrontal, vlPFC, cortices to the STN). When informing the tract solely based on one cohort (e.g. ALIC), clinical improvements in the other (e.g. STN) could be significantly predicted, and vice versa. Finally, clinical improvements of eight patients from a third center with electrodes in the NAcc and six patients from a fourth center in which electrodes had been implanted in both STN and ALIC were significantly predicted based on this novel tract-based DBS target. Results suggest a functional role of a limbic hyperdirect pathway that projects from dACC and vlPFC to anteriomedial STN. Obsessive-compulsive symptoms seem to be tractable by modulating the specific bundle isolated here. Our results show that connectivity-derived improvement models can inform clinical improvement across DBS targets, surgeons and centers. The identified tract is now three-dimensionally defined in stereotactic standard space and will be made openly available.

Open-label trial of anterior limb of internal capsule–nucleus accumbens deep brain stimulation for obsessive-compulsive disorder: insights gained

2019 ◽  
Vol 90 (7) ◽  
pp. 805-812 ◽  
Author(s):  
Daniel Huys ◽  
Sina Kohl ◽  
Juan Carlos Baldermann ◽  
Lars Timmermann ◽  
Volker Sturm ◽  
...  
Keyword(s):  
Deep Brain Stimulation ◽  
Nucleus Accumbens ◽  
Executive Functions ◽  
Obsessive Compulsive Disorder ◽  
Brain Stimulation ◽  
Internal Capsule ◽  
Obsessive Compulsive ◽  
Open Label ◽  
Compulsive Disorder ◽  
Deep Brain

BackgroundFor more than 15 years, deep brain stimulation (DBS) has served as a last-resort treatment for severe treatment-resistant obsessive-compulsive disorder (OCD).MethodsFrom 2010 to 2016, 20 patients with OCD (10 men/10 women) were included in a single-centre trial with a naturalistic open-label design over 1 year to evaluate the effects of DBS in the anterior limb of the internal capsule and nucleus accumbens region (ALIC-NAcc) on OCD symptoms, executive functions, and personality traits.ResultsALIC-NAcc-DBS significantly decreased OCD symptoms (mean Yale-Brown Obsessive Compulsive Scale reduction 33%, 40% full responders) and improves global functioning without loss of efficacy over 1 year. No significant changes were found in depressive or anxiety symptoms. Our study did not show any effect of ALIC-NAcc-DBS on personality traits or executive functions, and no potential outcome predictors were identified in a post hoc analysis. Other than several individual minor adverse events, ALIC-NAcc-DBS has been shown to be safe, but 35% of patients reported a sudden increase in anxiety and anhedonia after acute cessation of stimulation.ConclusionsWe conclude that ALIC-NAcc-DBS is a well-tolerated and promising last-resort treatment option for OCD. The cause of variability in the outcome remains unclear, and the aspect of reversibility must be examined critically. The present data from one of the largest samples of patients with OCD treated with DBS thus far support the results of previous studies with smaller samples.

Susceptibility Sensitive Magnetic Resonance Imaging Displays Pallidofugal and Striatonigral Fiber Tracts

2016 ◽  
Vol 12 (4) ◽  
pp. 330-338 ◽  
Author(s):  
Till M Schneider ◽  
Andreas Deistung ◽  
Uta Biedermann ◽  
Cordula Matthies ◽  
Ralf-Ingo Ernestus ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Deep Brain Stimulation ◽  
Magnetic Resonance ◽  
Brain Stimulation ◽  
Internal Capsule ◽  
Resonance Imaging ◽  
Gradient Echo ◽  
Fiber Tracts ◽  
Deep Brain

BACKGROUND The pallidofugal and striatonigral fiber tracts form a functional part of the basal ganglionic neuronal networks. For deep brain stimulation, a surgical procedure applied in the treatment of Parkinson disease and dystonia, precise localization of pallidofugal pathways may be of particular clinical relevance for correct electrode positioning. OBJECTIVE To investigate whether the pallidofugal and striatonigral pathways can be visualized with magnetic resonance imaging in vivo by exploiting their intrinsic magnetic susceptibility. METHODS Three-dimensional gradient-echo imaging of 5 volunteers was performed on a 7 T magnetic resonance imaging system. To demonstrate that the displayed tubular structures in the vicinity of the subthalamic nucleus and substantia nigra truly represent fiber tracts rather than veins, gradient-echo data of a formalin-fixated brain and a volunteer during inhalation of ambient air and carbogen were collected at 3 T. Susceptibility weighted images, quantitative susceptibility maps, and effective transverse relaxation maps were reconstructed and the depiction of fiber tracts was qualitatively assessed. RESULTS High-resolution susceptibility-based magnetic resonance imaging contrasts enabled visualization of pallidofugal and striatonigral fiber tracts noninvasively at 3 T and 7 T. We verified that the stripe-like pattern observed on susceptibility-sensitive images is not caused by veins crossing the internal capsule but by fiber tracts traversing the internal capsule. CONCLUSION Pallidofugal and striatonigral fiber tracts have been visualized in vivo for the first time by using susceptibility-sensitive image contrasts. Considering the course of pallidofugal pathways, in particular for deep brain stimulation procedures in the vicinity of the subthalamic nucleus, could provide landmarks for optimal targeting during stereotactic planning.

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