Dataset Information

Parallel transmission to reduce absorbed power around deep brain stimulation devices in MRI: Impact of number and arrangement of transmit channels.

ABSTRACT:

Purpose

To assess the mean and variance performance of parallel transmission (pTx) coils for reduction of the absorbed power around electrodes (APAE) in patients implanted with deep brain stimulation (DBS) devices.

Methods

We simulated 4 pTx coils (8 and 16 channels, head and body coils) and a birdcage body coil. We characterized the RF safety risk using the APAE, which is the integral of the deposited power (in Watts) in a small cylindrical volume of brain tissue surrounding the electrode tips. We assessed the APAE mean and variance by simulation of 5 realistic DBS patient models that include the full DBS implant length, extracranial loops, and implanted pulse generator.

Results

PTx coils with 8 (16) channels were able to reduce the APAE by >18× (>169×) compared to the birdcage coil in average for all patient models, at no cost in term of flip angle uniformity or global specific absorption rate (SAR). Moreover, local pTx coils performed significantly better than body arrays.

Conclusion

PTx is a possible solution to the problem of RF heating of DBS patients when performing MRI, but the large interpatient variability of the APAE indicates that patient-specific safety monitoring may be needed.

SUBMITTER: Guerin B

PROVIDER: S-EPMC6778698 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Parallel transmission to reduce absorbed power around deep brain stimulation devices in MRI: Impact of number and arrangement of transmit channels.

Guerin Bastien B Angelone Leonardo M LM Dougherty Darin D Wald Lawrence L LL

Magnetic resonance in medicine 20190807 1

<h4>Purpose</h4>To assess the mean and variance performance of parallel transmission (pTx) coils for reduction of the absorbed power around electrodes (APAE) in patients implanted with deep brain stimulation (DBS) devices.<h4>Methods</h4>We simulated 4 pTx coils (8 and 16 channels, head and body coils) and a birdcage body coil. We characterized the RF safety risk using the APAE, which is the integral of the deposited power (in Watts) in a small cylindrical volume of brain tissue surrounding the ...[more]

PMID: 31389069

Similar Datasets

Project description:BackgroundDeep brain stimulation (DBS) is an established treatment for patients with movement disorders. Patients receiving chronic DBS provide a unique opportunity to explore the underlying mechanisms of DBS using functional MRI. It has been shown that the main safety concern with MRI in these patients is heating at the electrode tips - which can be minimised with strict adherence to a supervised acquisition protocol using a head-transmit/receive coil at 1.5T. MRI using the body-transmit coil with a multi-channel receive head coil has a number of potential advantages including an improved signal-to-noise ratio.Study outlineWe compared the safety of cranial MRI in an in vitro model of bilateral DBS using both head-transmit and body-transmit coils. We performed fibre-optic thermometry at a Medtronic ActivaPC device and Medtronic 3389 electrodes during turbo-spin echo (TSE) MRI using both coil arrangements at 1.5T and 3T, in addition to gradient-echo echo-planar fMRI exposure at 1.5T. Finally, we investigated the effect of transmit-coil choice on DBS stimulus delivery during MRI.ResultsTemperature increases were consistently largest at the electrode tips. Changing from head- to body-transmit coil significantly increased the electrode temperature elevation during TSE scans with scanner-reported head SAR 0.2W/kg from 0.45°C to 0.79°C (p<0.001) at 1.5T, and from 1.25°C to 1.44°C (p<0.001) at 3T. The position of the phantom relative to the body coil significantly impacted on electrode heating at 1.5T; however, the greatest heating observed in any position tested remained <1°C at this field strength.ConclusionsWe conclude that (1) with our specific hardware and SAR-limited protocol, body-transmit cranial MRI at 1.5T does not produce heating exceeding international guidelines, even in cases of poorly positioned patients, (2) cranial MRI at 3T can readily produce heating exceeding international guidelines, (3) patients with ActivaPC Medtronic systems are safe to be recruited to future fMRI experiments performed under the specific conditions defined by our protocol, with no likelihood of confound by inappropriate stimulus delivery.

Dataset Information

Parallel transmission to reduce absorbed power around deep brain stimulation devices in MRI: Impact of number and arrangement of transmit channels.

Purpose

Methods

Results

Conclusion

Publications

Parallel transmission to reduce absorbed power around deep brain stimulation devices in MRI: Impact of number and arrangement of transmit channels.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets