scholarly journals Effect of Device Configuration and Patient's Body Composition on the RF Heating and Nonsusceptibility Artifact of Deep Brain Stimulation Implants During MRI at 1.5T and 3T

2020 ◽  
Author(s):  
Bhumi Bhusal ◽  
Bach T. Nguyen ◽  
Pia P. Sanpitak ◽  
Jasmine Vu ◽  
Behzad Elahi ◽  
...  
Keyword(s):  
Body Composition ◽  
Deep Brain Stimulation ◽  
Brain Stimulation ◽  
Rf Heating ◽  
Deep Brain

scholarly journals The effect of device configuration and patient’s body composition on image artifact and RF heating of deep brain stimulation devices during MRI at 1.5T and 3T

2020 ◽  
Author(s):  
Bhumi Bhusal ◽  
Bach T. Nguyen ◽  
Jasmine Vu ◽  
Behzad Elahi ◽  
Joshua Rosenow ◽  
...  
Keyword(s):  
Body Composition ◽  
Deep Brain Stimulation ◽  
Brain Stimulation ◽  
Statistical Tests ◽  
Subcutaneous Fat ◽  
Rf Heating ◽  
Worst Case ◽  
Image Artifact ◽  
Lead Configuration ◽  
Deep Brain

AbstractBACKGROUNDPatients with deep brain stimulation (DBS) implants have limited access to MRI due to safety concerns associated with RF-induced heating. Currently, MRI in these patients is allowed only in 1.5T horizontal scanners and with pulse sequences with reduced power. Nevertheless, off-label use of MRI at 3T is increasingly reported based on limited safety assessments. Here we present results of systematic RF heating measurements for two commercially available DBS systems during MRI at 1.5T and 3T.PURPOSETo assess the effect of imaging landmark, DBS lead configuration, and patient body composition on RF heating of DBS leads during MRI at 1.5 T and 3T.STUDY TYPEPhantom study.POPULATION/SUBJECTS/PHANTOM/SPECIMEN/ANIMAL MODELGel phantoms and cadaver brain.FIELD STRENGTH/SEQUENCE1.5T and 3T, T1-weighted turbo spin echo.ASSESSMENTRF heating was measured at tips of DBS leads implanted in brain-mimicking gel.STATISTICAL TESTSNone.RESULTSWe observed substantial fluctuation in RF heating mainly affected by phantom composition and DBS lead configuration, ranging from 0.14°C to 23.73°C at 1.5 T, and from 0.10°C to 7.39°C at 3T. The presence of subcutaneous fat substantially altered RF heating at electrode tips (−3.06°C < ΔT < 19.05°C). Introducing concentric loops in the extracranial portion of the lead at the surgical burr hole reduced RF heating by up to 89% at 1.5T and up to 98% at 3T compared to worst case heating scenarios.DATA CONCLUSIONDevice configuration and patient body composition significantly altered the RF heating of DBS leads during MRI at 1.5T and 3T. Interestingly, certain lead trajectories consistently reduced RF heating and image artifact over different imaging landmarks, RF frequencies, and phantom compositions. Such trajectories could be implemented in patients with minimal disruption to the surgical workflow.

scholarly journals Reconfigurable MRI coil technology can substantially reduce RF heating at the tips of bilateral deep brain stimulation implants

2018 ◽  
Author(s):  
Laleh Golestanirad ◽  
Boris Keil ◽  
Sean Downs ◽  
John Kirsch ◽  
Behzad Elahi ◽  
...  
Keyword(s):  
Deep Brain Stimulation ◽  
Brain Stimulation ◽  
Temperature Rise ◽  
Substantial Reduction ◽  
The Body ◽  
Rf Heating ◽  
Coil System ◽  
Body Coil ◽  
Magnetic Resonance Imaging Mri ◽  
Deep Brain

AbstractPatients with deep brain stimulation (DBS) implants can significantly benefit from magnetic resonance imaging (MRI) examination, however, access to MRI is restricted in this patients because of safety concerns due to RF heating of the leads. Recently we introduced a patient-adjustable reconfigurable MRI coil system to reduce the SAR at the tip of deep brain stimulation implants during MRI at 1.5T. A simulation study with realistic models of single (unilateral) DBS leads demonstrated a substantial reduction in the local SAR up to 500-fold could be achieved using the coil system compared to quadrature birdcage coils. Many patients however, have bilateral DBS implants and the question arises whether the rotating coil system can be used in for them. This work reports the results of phantom experiments measuring the temperature rise at the tips of bilateral DBS implants with realistic trajectories extracted from postoperative CT images of 10 patients (20 leads in total). A total of 200 measurements were performed to record temperature rise at the tips of the leads during 2 minutes of scanning with the coil rotated to cover all accessible rotation angles. In all patients, we were able to find an optimum coil rotation angle and reduced the heating of both left and right leads to a level below the heating produced by the body coil. An average heat reduction of 65% was achieved for bilateral leads. Reconfigurable coil technology introduces a promising approach for imaging of patients with DBS implants.

scholarly journals Reconfigurable MRI coil technology can substantially reduce RF heating of deep brain stimulation implants: First in-vitro study of RF heating reduction in bilateral DBS leads at 1.5 T

PLoS ONE ◽  
2019 ◽  
Vol 14 (8) ◽  
pp. e0220043 ◽  
Author(s):  
Laleh Golestanirad ◽  
Ehsan Kazemivalipour ◽  
Boris Keil ◽  
Sean Downs ◽  
John Kirsch ◽  
...  
Keyword(s):  
Deep Brain Stimulation ◽  
Brain Stimulation ◽  
In Vitro Study ◽  
Vitro Study ◽  
Rf Heating ◽  
Deep Brain

scholarly journals RF heating of deep brain stimulation implants in open-bore vertical MRI systems

2019 ◽  
Author(s):  
Laleh Golestanirad ◽  
David Lampman ◽  
Ehsan Kazemivalipour ◽  
Hideta Habara ◽  
Ergin Atalar ◽  
...  
Keyword(s):  
Deep Brain Stimulation ◽  
Functional Mri ◽  
Brain Stimulation ◽  
Rf Heating ◽  
Medical Implants ◽  
Safety Hazards ◽  
Electromagnetic Simulations ◽  
Fold Reduction ◽  
Electric And Magnetic Fields ◽  
Deep Brain

AbstractPurposePatients with deep brain stimulation (DBS) implants highly benefit from MRI, however access to MRI is restricted for these patients due to safety hazards associated with RF heating of the implant. To date, all MRI studies on RF heating of medical implants have been performed in horizontal closed-bore systems. Vertical MRI scanners have a fundamentally different distribution of electric and magnetic fields and are now available at 1.2T, capable of high-resolution structural and functional MRI. This work presents the first simulation study of RF heating of DBS implants in high-field vertical scanners.MethodsWe performed finite element electromagnetic simulations to calculate SAR at tips of DBS leads during MRI in a commercially available 1.2 T vertical coil compared to a 1.5 T horizontal scanner. Both isolated leads and fully implanted systems were included.ResultsWe found 10-30-fold reduction in SAR implication at tips of isolated DBS leads, and up to 19-fold SAR reduction at tips of leads in fully implanted systems in vertical coils compared to horizontal birdcage coils.ConclusionsIf confirmed in larger patient cohorts and verified experimentally, this result can open the door to plethora of structural and functional MRI applications to guide, interpret, and advance DBS therapy.

scholarly journals Safety and image quality at 7T MRI for deep brain stimulation systems: Ex vivo study with lead-only and full-systems

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257077
Author(s):  
Bhumi Bhusal ◽  
Jason Stockmann ◽  
Bastien Guerin ◽  
Azma Mareyam ◽  
John Kirsch ◽  
...  
Keyword(s):  
Deep Brain Stimulation ◽  
Image Quality ◽  
Brain Stimulation ◽  
High Field ◽  
Test Method ◽  
Rf Heating ◽  
Ultra High Field ◽  
High Field Mri ◽  
Ultra High Field Mri ◽  
Deep Brain

Ultra-high field MRI at 7 T can produce much better visualization of sub-cortical structures compared to lower field, which can greatly help target verification as well as overall treatment monitoring for patients with deep brain stimulation (DBS) implants. However, use of 7 T MRI for such patients is currently contra-indicated by guidelines from the device manufacturers due to the safety issues. The aim of this study was to provide an assessment of safety and image quality of ultra-high field magnetic resonance imaging at 7 T in patients with deep brain stimulation implants. We performed experiments with both lead-only and complete DBS systems implanted in anthropomorphic phantoms. RF heating was measured for 43 unique patient-derived device configurations. Magnetic force measurements were performed according to ASTM F2052 test method, and device integrity was assessed before and after experiments. Finally, we assessed electrode artifact in a cadaveric brain implanted with an isolated DBS lead. RF heating remained below 2°C, similar to a fever, with the 95% confidence interval between 0.38°C-0.52°C. Magnetic forces were well below forces imposed by gravity, and thus not a source of concern. No device malfunctioning was observed due to interference from MRI fields. Electrode artifact was most noticeable on MPRAGE and T2*GRE sequences, while it was minimized on T2-TSE images. Our work provides the safety assessment of ultra-high field MRI at 7 T in patients with DBS implants. Our results suggest that 7 T MRI may be performed safely in patients with DBS implants for specific implant models and MRI hardware.

An Open-Label Clinical Trial of Hypothalamic Deep Brain Stimulation for Human Morbid Obesity: BLESS Study Protocol

Neurosurgery ◽  
2018 ◽  
Vol 83 (4) ◽  
pp. 800-809 ◽  
Author(s):  
Antonio A F De Salles ◽  
Daniel A N Barbosa ◽  
Fernando Fernandes ◽  
Julio Abucham ◽  
Debora M Nazato ◽  
...  
Keyword(s):  
Morbid Obesity ◽  
Weight Loss ◽  
Body Composition ◽  
Electrical Stimulation ◽  
Deep Brain Stimulation ◽  
Side Effects ◽  
Food Intake ◽  
Brain Stimulation ◽  
Open Label ◽  
Deep Brain

Abstract BACKGROUND Human morbid obesity is increasing worldwide in an alarming way. The hypothalamus is known to mediate its mechanisms. Deep brain stimulation (DBS) of the ventromedial hypothalamus (VMH) may be an alternative to treat patients refractory to standard medical and surgical therapies. OBJECTIVE To assess the safety, identify possible side effects, and to optimize stimulation parameters of continuous VMH-DBS. Additionally, this study aims to determine if continuous VMH-DBS will lead to weight loss by causing changes in body composition, basal metabolism, or food intake control. METHODS The BLESS study is a feasibility study, single-center open-label trial. Six patients (body mass index &gt; 40) will undergo low-frequency VMH-DBS. Data concerning timing, duration, frequency, severity, causal relationships, and associated electrical stimulation patterns regarding side effects or weight changes will be recorded. EXPECTED OUTCOMES We expect to demonstrate the safety, identify possible side effects, and to optimize electrophysiological parameters related to VMH-DBS. No clinical or behavioral adverse changes are expected. Weight loss ≥ 3% of the basal weight after 3 mo of electrical stimulation will be considered adequate. Changes in body composition and increase in basal metabolism are expected. The amount of food intake is likely to remain unchanged. DISCUSSION The design of this study protocol is to define the safety of the procedure, the surgical parameters important for target localization, and additionally the safety of long-term stimulation of the VMH in morbidly obese patients. Novel neurosurgical approaches to treat metabolic and autonomic diseases can be developed based on the data made available by this investigation.

scholarly journals RF heating of deep brain stimulation implants in open‐bore vertical MRI systems: A simulation study with realistic device configurations

2019 ◽  
Vol 83 (6) ◽  
pp. 2284-2292 ◽  
Author(s):  
Laleh Golestanirad ◽  
Ehsan Kazemivalipour ◽  
David Lampman ◽  
Hideta Habara ◽  
Ergin Atalar ◽  
...  
Keyword(s):  
Deep Brain Stimulation ◽  
Brain Stimulation ◽  
Simulation Study ◽  
Rf Heating ◽  
Deep Brain
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