Use of probabilistic tractography to provide reliable distinction of the motor and sensory thalamus for prospective targeting during asleep deep brain stimulation

2021 ◽  
pp. 1-10
Author(s):  
Jennifer Muller ◽  
Mahdi Alizadeh ◽  
Caio M. Matias ◽  
Sara Thalheimer ◽  
Victor Romo ◽  
...  
Keyword(s):  
Deep Brain Stimulation ◽  
Brain Stimulation ◽  
Diffusion Imaging ◽  
Probabilistic Methods ◽  
Electrode Placement ◽  
Probabilistic Tractography ◽  
Similarity Coefficients ◽  
Deterministic Tractography ◽  
Sensory Fibers ◽  
Deep Brain

OBJECTIVE Accurate electrode placement is key to effective deep brain stimulation (DBS). The ventral intermediate nucleus (VIM) of the thalamus is an established surgical target for the treatment of essential tremor (ET). Retrospective tractography-based analysis of electrode placement has associated successful outcomes with modulation of motor input to VIM, but no study has yet evaluated the feasibility and efficacy of prospective presurgical tractography-based targeting alone. Therefore, the authors sought to demonstrate the safety and efficacy of probabilistic tractography–based VIM targeting in ET patients and to perform a systematic comparison of probabilistic and deterministic tractography. METHODS Fourteen patients with ET underwent preoperative diffusion imaging. Probabilistic tractography was applied for preoperative targeting, and deterministic tractography was performed as a comparison between methods. Tractography was performed using the motor and sensory areas as initiation seeds, the ipsilateral thalamus as an inclusion mask, and the contralateral dentate nucleus as a termination mask. Tract-density maps consisted of voxels with 10% or less of the maximum intensity and were superimposed onto anatomical images for presurgical planning. Target planning was based on probabilistic tract-density images and indirect target coordinates. Patients underwent robotic image-guided, image-verified implantation of directional DBS systems. Postoperative tremor scores with and without DBS were recorded. The center of gravity and Dice similarity coefficients were calculated and compared between tracking methods. RESULTS Prospective probabilistic targeting of VIM was successful in all 14 patients. All patients experienced significant tremor reduction. Formal postoperative tremor scores were available for 9 patients, who demonstrated a mean 68.0% tremor reduction. Large differences between tracking methods were observed across patients. Probabilistic tractography–identified VIM fibers were more anterior, lateral, and superior than deterministic tractography–identified fibers, whereas probabilistic tractography–identified ventralis caudalis fibers were more posterior, lateral, and superior than deterministic tractography–identified fibers. Deterministic methods were unable to clearly distinguish between motor and sensory fibers in the majority of patients, but probabilistic methods produced distinct separation. CONCLUSIONS Probabilistic tractography–based VIM targeting is safe and effective for the treatment of ET. Probabilistic tractography is more precise than deterministic tractography for the delineation of VIM and the ventralis caudalis nucleus of the thalamus. Deterministic algorithms tended to underestimate separation between motor and sensory fibers, which may have been due to its limitations with crossing fibers. Larger studies across multiple centers are necessary to further validate this method.

Clinical outcomes of asleep vs awake deep brain stimulation for Parkinson disease

Neurology ◽  
2017 ◽  
Vol 89 (19) ◽  
pp. 1944-1950 ◽  
Author(s):  
Matthew A. Brodsky ◽  
Shannon Anderson ◽  
Charles Murchison ◽  
Mara Seier ◽  
Jennifer Wilhelm ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Deep Brain Stimulation ◽  
Parkinson Disease ◽  
Brain Stimulation ◽  
Electrode Placement ◽  
Microelectrode Recording ◽  
Imaging Guidance ◽  
Motor Outcomes ◽  
Deep Brain

Objective:To compare motor and nonmotor outcomes at 6 months of asleep deep brain stimulation (DBS) for Parkinson disease (PD) using intraoperative imaging guidance to confirm electrode placement vs awake DBS using microelectrode recording to confirm electrode placement.Methods:DBS candidates with PD referred to Oregon Health & Science University underwent asleep DBS with imaging guidance. Six-month outcomes were compared to those of patients who previously underwent awake DBS by the same surgeon and center. Assessments included an “off”-levodopa Unified Parkinson’s Disease Rating Scale (UPDRS) II and III, the 39-item Parkinson's Disease Questionnaire, motor diaries, and speech fluency.Results:Thirty participants underwent asleep DBS and 39 underwent awake DBS. No difference was observed in improvement of UPDRS III (+14.8 ± 8.9 vs +17.6 ± 12.3 points, p = 0.19) or UPDRS II (+9.3 ± 2.7 vs +7.4 ± 5.8 points, p = 0.16). Improvement in “on” time without dyskinesia was superior in asleep DBS (+6.4 ± 3.0 h/d vs +1.7 ± 1.2 h/d, p = 0.002). Quality of life scores improved in both groups (+18.8 ± 9.4 in awake, +8.9 ± 11.5 in asleep). Improvement in summary index (p = 0.004) and subscores for cognition (p = 0.011) and communication (p < 0.001) were superior in asleep DBS. Speech outcomes were superior in asleep DBS, both in category (+2.77 ± 4.3 points vs −6.31 ± 9.7 points (p = 0.0012) and phonemic fluency (+1.0 ± 8.2 points vs −5.5 ± 9.6 points, p = 0.038).Conclusions:Asleep DBS for PD improved motor outcomes over 6 months on par with or better than awake DBS, was superior with regard to speech fluency and quality of life, and should be an option considered for all patients who are candidates for this treatment.Clinicaltrials.gov identifier:NCT01703598.Classification of evidence:This study provides Class III evidence that for patients with PD undergoing DBS, asleep intraoperative CT imaging–guided implantation is not significantly different from awake microelectrode recording–guided implantation in improving motor outcomes at 6 months.

Avoiding the ventricle: a simple step to improve accuracy of anatomical targeting during deep brain stimulation

2009 ◽  
Vol 110 (6) ◽  
pp. 1283-1290 ◽  
Author(s):  
Ludvic Zrinzo ◽  
Arjen L. J. van Hulzen ◽  
Alessandra A. Gorgulho ◽  
Patricia Limousin ◽  
Michiel J. Staal ◽  
...  
Keyword(s):  
Deep Brain Stimulation ◽  
Brain Stimulation ◽  
Electrode Placement ◽  
Neurosurgical Procedures ◽  
Electrode Implantation ◽  
Clinical Observations ◽  
Simple Step ◽  
The Mean ◽  
The Impact ◽  
Deep Brain

Object The authors examined the accuracy of anatomical targeting during electrode implantation for deep brain stimulation in functional neurosurgical procedures. Special attention was focused on the impact that ventricular involvement of the electrode trajectory had on targeting accuracy. Methods The targeting error during electrode placement was assessed in 162 electrodes implanted in 109 patients at 2 centers. The targeting error was calculated as the shortest distance from the intended stereotactic coordinates to the final electrode trajectory as defined on postoperative stereotactic imaging. The trajectory of these electrodes in relation to the lateral ventricles was also analyzed on postoperative images. Results The trajectory of 68 electrodes involved the ventricle. The targeting error for all electrodes was calculated: the mean ± SD and the 95% CI of the mean was 1.5 ± 1.0 and 0.1 mm, respectively. The same calculations for targeting error for electrode trajectories that did not involve the ventricle were 1.2 ± 0.7 and 0.1 mm. A significantly larger targeting error was seen in trajectories that involved the ventricle (1.9 ± 1.1 and 0.3 mm; p < 0.001). Thirty electrodes (19%) required multiple passes before final electrode implantation on the basis of physiological and/or clinical observations. There was a significant association between an increased requirement for multiple brain passes and ventricular involvement in the trajectory (p < 0.01). Conclusions Planning an electrode trajectory that avoids the ventricles is a simple precaution that significantly improves the accuracy of anatomical targeting during electrode placement for deep brain stimulation. Avoidance of the ventricles appears to reduce the need for multiple passes through the brain to reach the desired target as defined by clinical and physiological observations.

Postural Instability and Gait Disorder After Subthalamic Nucleus Deep Brain Stimulation

2020 ◽  
pp. 119-124
Author(s):  
Mónica M. Kurtis ◽  
Javier R. Pérez-Sánchez
Keyword(s):  
Deep Brain Stimulation ◽  
Subthalamic Nucleus ◽  
Brain Stimulation ◽  
Synergistic Effects ◽  
Disease Onset ◽  
Postural Instability ◽  
Electrode Placement ◽  
Medication Side ◽  
Balance Problems ◽  
Deep Brain

Parkinson disease (PD) patients who have undergone surgery and develop festinating gait and postural instability are challenging to diagnose and treat. This chapter describes the case of an early-onset PD patient who underwent deep brain stimulation (DBS) 4 years after disease onset due to motor and nonmotor fluctuations and medication side effects (impulse control disorder). A year after surgery, the patient developed gait and balance problems in the on-medication/on-stimulation states that resolved after turning stimulation off or withdrawing medication for 12 hours. However, other symptoms, including as bradykinesia, rigidity, and tremor, reappeared. Troubleshooting involved magnetic resonance imaging to evaluate electrode placement and complete screening of all contacts with successful reprogramming and medication adjustments. The pathophysiology of balance problems is discussed, including the synergistic effects of subthalamic nucleus DBS and dopaminergic treatment, which may lead to increased postural sway and lower limb dystonia.

scholarly journals Clinically Weighted Probabilistic Tractography Mapping of Therapeutic Thalamic Deep Brain Stimulation for Essential Tremor

Neurosurgery ◽  
2019 ◽  
Vol 66 (Supplement_1) ◽  
Author(s):  
Evangelia Tsolaki ◽  
Alon Kashanian ◽  
Nader Pouratian
Keyword(s):  
Deep Brain Stimulation ◽  
Clinical Outcome ◽  
Essential Tremor ◽  
Clinical Improvement ◽  
Brain Stimulation ◽  
Structural Connectivity ◽  
Precentral Gyrus ◽  
Probabilistic Tractography ◽  
Whole Brain ◽  
Deep Brain

Abstract INTRODUCTION Traditional targeting methods rely on indirect targeting with atlas-defined coordinates that induce interpatient anatomical and functional variability. Precise targeting is crucial for successful surgical intervention associated with improved surgical outcomes. Here, we use clinically weighted probabilistic tractography to investigate the connectivity from volume of tissue activated (VTA) to whole brain in order to evaluate the relationship between structural connectivity and clinical outcome of patients that underwent thalamic deep brain stimulation (DBS). METHODS Magnetic resonance imaging and clinical outcomes from 10 essential tremor (ET) patients who were treated by VIM-DBS at the University of California Los Angeles were evaluated. LeadBDS was used for the VTA calculation and FSL was used to evaluate the whole brain probabilistic tractography of VTA. Tractography maps were binarized and weighted based on the percent of clinical improvement using the Fahn-Tolosa-Martin Tremor Rating Score. The resulting clinically weighted maps were non-linearly fused to MNI space and averaged. These population maps provide a voxel-by-voxel map of the average clinical improvement observed when the VTA demonstrates structural connectivity to the whole brain. RESULTS The VTA connectivity to the whole brain was delineated. Superior clinical improvement was associated with connectivity to voxels connecting the thalamus to the precentral gyrus and to the brainstem/cerebellum. Also, the clinical efficacy map showed that patients with higher clinical improvement (>70%) presented stronger structural connectivity to the precentral gyrus and to the caudal projection to the cerebellum. CONCLUSION Stronger connectivity to the precentral gyrus and to brainstem/cerebellum is associated with superior clinical outcome in thalamic DBS for ET. In the future, rather than focusing on connectivity to predetermined targets, these clinically weighted tractography maps can be used with a reverse algorithm to identify the optimal region of the thalamus to provide clinically superior results.

Improving Targeting in Image-Guided Frame-Based Deep Brain Stimulation

2010 ◽  
Vol 67 (suppl_2) ◽  
pp. ons437-ons447 ◽  
Author(s):  
Etienne M. Holl ◽  
Erika A. Petersen ◽  
Thomas Foltynie ◽  
Irene Martinez-Torres ◽  
Patricia Limousin ◽  
...  
Keyword(s):  
Deep Brain Stimulation ◽  
Standard Deviation ◽  
Brain Stimulation ◽  
Rating Scale ◽  
Electrode Placement ◽  
Target Point ◽  
Intended Target ◽  
Image Guided ◽  
Significant Difference ◽  
Deep Brain

ABSTRACT BACKGROUND: Deep brain stimulation (DBS) is commonly used in the treatment of movement disorders such as Parkinson disease (PD), dystonia, and other tremors. OBJECTIVE: To examine systematic errors in image-guided DBS electrode placement and to explore a calibration strategy for stereotactic targeting. METHODS: Pre- and postoperative stereotactic MR images were analyzed in 165 patients. The perpendicular error between planned target coordinates and electrode trajectory was calculated geometrically for all 312 DBS electrodes implanted. Improvement in motor unified PD rating scale III subscore was calculated for those patients with PD with at least 6 months of follow-up after bilateral subthalamic DBS. RESULTS: Mean (standard deviation) scalar error of all electrodes was 1.4(0.9) mm with a significant difference between left and right hemispheres. Targeting error was significantly higher for electrodes with coronal approach angle (ARC) ≥10° (P &lt; .001). Mean vector error was X: −0.6, Y: −0.7, and Z: −0.4 mm (medial, posterior, and superior directions, respectively). Targeting error was significantly improved by using a systematic calibration strategy based on ARC and target hemisphere (mean: 0.6 mm, P &lt; .001) for 47 electrodes implanted in 24 patients. Retrospective theoretical calibration for all 312 electrodes would have reduced the mean (standard deviation) scalar error from 1.4(0.9) mm to 0.9(0.5) mm (36% improvement). With calibration, 97% of all electrodes would be within 2 mm of the intended target as opposed to 81% before calibration. There was no significant correlation between the degree of error and clinical outcome from bilateral subthalamic nucleus DBS (R2 = 0.07). CONCLUSION: After calibration of a systematic targeting error an MR image-guided stereotactic approach would be expected to deliver 97% of all electrodes to within 2 mm of the intended target point with a single brain pass.

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