Functional MRI Safety and Artifacts during Deep Brain Stimulation: Experience in 102 Patients

Boutet, Alexandre; Rashid, Tanweer; Hancu, Ileana; Elias, Gavin J B; Gramer, Robert; Germann, Jürgen; DiMarzio, Marisa; Li, Bryan; Paramanandam, Vijayashankar; Prasad, Shiva; Ranjan, Manish; Coblentz, Ailish; Gwun, Dave; Chow, Chung‐Wai; Maciel, Ricardo; Soh, Derrick; Fiveland, Eric; Hodaie, Mojgan; Kalia, Suneil K.; Fasano, Alfonso; Kucharczyk, Walter; Pilitsis, Julie G.; Lozano, Andrés M.

doi:10.1148/radiol.2019190546

Cited by 58 publications

(41 citation statements)

References 31 publications

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“…For higher heating cases, significant B1 + distortion is produced not only by the intracranial part of the DBS lead, but also by the extracranial portions of the lead and extension. The results are consistent with earlier studies involving variation of RF heating and B1 + field inhomogeneity/image artifacts [14], [48].…”

Section: B Resultssupporting

confidence: 92%

Application of Surgical Lead Management and Reconfigurable Coil Technology to Reduce RF Heating of DBS Implants during MRI at 3T Under Variant Body Compositions

Bhusal¹,

Elahi²,

Keil

et al. 2020

Preprint

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Patients with active implants such as deep brain stimulation (DBS) devices, have limited access to magnetic resonance imaging (MRI) due to risks of RF heating. With an aging population, the prevalence of neurodegenerative and vascular disease increases; and so does the indication for MRI exams in patients with such implants. In response to this growing need for MRI, many groups have investigated strategies to mitigate the RF heating of the implants. These efforts, however, have relied either on simulations with homogenous body models or simplified phantom experiments (box shaped phantom with single tissue). It is well established, however, that the shape and heterogeneity of human body affects the distribution of MRI electric fields, which by proxy, alters the RF heating of an implant inside the body. In this contribution, we applied numerical simulations and phantom experiments to examine the effectiveness of RF heating mitigation strategies under variant patient body compositions, focusing on two recently proposed techniques: (a) surgical modification of DBS lead trajectories inside the body, and (b) use of a patient-adjustable reconfigurable MRI coil, both aiming to reduce the coupling of implanted leads and MRI electric fields. Our results demonstrated that both techniques perform well under variant body compositions.Index Terms-Body model, implant safety, finite element, magnetic resonance imaging (MRI), RF heating, simulation, specific absorption rate (SAR), transmit coil. J. Rosenow is with

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Section: B Resultssupporting

confidence: 92%

Application of Surgical Lead Management and Reconfigurable Coil Technology to Reduce RF Heating of DBS Implants during MRI at 3T Under Variant Body Compositions

Bhusal¹,

Elahi²,

Keil

et al. 2020

Preprint

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“…Such off-label studies have relied on in-home safety assessments mostly performed in ASTM-like Phantoms (i.e., the box shaped phantom filled with a single material), and with limited number of DBS device configurations (12,13). This oversimplified approach to MRI safety assessment is concerning for two reasons.…”

Section: Resultsmentioning

confidence: 99%

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

Bhusal¹,

Nguyen²,

Vu³

et al. 2020

Preprint

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BACKGROUNDPatients 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. from 0.10℃ to 7.39℃ at 3T. The presence of subcutaneous fat substantially altered RF heating at electrode tips (-3.06℃ < ∆ < 19.05℃). 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.

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“…13,15 The majority of human studies have been carried out using 1.5T MRI and suffer from small sample sizes and low reliability. [16][17][18][19] However, recent advances in 3T MRI-compatible DBS technology, which can now be safely applied to humans, [20][21][22] has provided an unprecedented opportunity for exploring specific but subtle changes in brain circuitry induced by DBS.…”

Section: Subthalamic Nucleus Deep Brain Stimulation (Stn-dbs) Has Becmentioning

confidence: 99%

Subthalamic Nucleus Deep Brain Stimulation Modulates 2 Distinct Neurocircuits

Shen

Jiang

Hubbard

et al. 2020

Annals of Neurology

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Objective: Current understanding of the neuromodulatory effects of deep brain stimulation (DBS) on large-scale brain networks remains elusive, largely due to the lack of techniques that can reveal DBS-induced activity at the whole-brain level. Using a novel 3T magnetic resonance imaging (MRI)-compatible stimulator, we investigated whole-brain effects of subthalamic nucleus (STN) stimulation in patients with Parkinson disease. Methods: Fourteen patients received STN-DBS treatment and participated in a block-design functional MRI (fMRI) experiment, wherein stimulations were delivered during "ON" blocks interleaved with "OFF" blocks. fMRI responses to low-frequency (60Hz) and high-frequency(130Hz) STN-DBS were measured 1, 3, 6, and 12 months postsurgery. To ensure reliability, multiple runs (48 minutes) of fMRI data were acquired at each postsurgical visit. Presurgical resting-state fMRI (30 minutes) data were also acquired. Results: Two neurocircuits showed highly replicable, but distinct responses to STN-DBS. A circuit involving the globus pallidus internus (GPi), thalamus, and deep cerebellar nuclei was significantly activated, whereas another circuit involving the primary motor cortex (M1), putamen, and cerebellum showed DBS-induced deactivation. These 2 circuits were dissociable in terms of their DBS-induced responses and resting-state functional connectivity. The GPi circuit was frequency-dependent, selectively responding to high-frequency stimulation, whereas the M1 circuit was responsive in a time-dependent manner, showing enhanced deactivation over time. Finally, activation of the GPi circuit was associated with overall motor improvement, whereas M1 circuit deactivation was related to reduced bradykinesia. Interpretation: Concurrent DBS-fMRI using 3T revealed 2 distinct circuits that responded differentially to STN-DBS and were related to divergent symptoms, a finding that may provide novel insights into the neural mechanisms underlying DBS.

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Functional MRI Safety and Artifacts during Deep Brain Stimulation: Experience in 102 Patients

Cited by 58 publications

References 31 publications

Application of Surgical Lead Management and Reconfigurable Coil Technology to Reduce RF Heating of DBS Implants during MRI at 3T Under Variant Body Compositions

Application of Surgical Lead Management and Reconfigurable Coil Technology to Reduce RF Heating of DBS Implants during MRI at 3T Under Variant Body Compositions

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

Subthalamic Nucleus Deep Brain Stimulation Modulates 2 Distinct Neurocircuits

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