Reducing RF-induced Heating near Implanted Leads through High-Dielectric Capacitive Bleeding of Current (CBLOC)

Golestanirad, Laleh; Angelone, Leonardo M.; Kirsch, John E.; Downs, Sean; Keil, Boris; Bonmassar, Giorgio; Wald, Lawrence L.

doi:10.1101/456533

Cited by 5 publications

(4 citation statements)

References 51 publications

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“…Efforts to make MRI accessible to patients with conductive implants have a long history, as is clear from the spate of patents published in the past two decades 32–41 . Most of the work has focused on modifying the implant itself, such as in the case of active implants by increasing the lead's impedance or altering the material to reduce induced RF currents 41–44 . This has had limited success, and the restrictions on MRI remain.…”

Section: Discussionmentioning

confidence: 99%

Modifying the trajectory of epicardial leads can substantially reduce MRI‐induced RF heating in pediatric patients with a cardiac implantable electronic device at 1.5T

Jiang,

Bhusal,

Nguyen

et al. 2023

Magnetic Resonance in Med

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PurposeAfter epicardial cardiac implantable electronic devices are implanted in pediatric patients, they become ineligible to receive MRI exams due to an elevated risk of RF heating. We investigated whether simple modifications in the trajectories of epicardial leads could substantially and reliably reduce RF heating during MRI at 1.5 T, with benefits extending to abandoned leads.MethodsElectromagnetic simulations were performed to assess RF heating of two common 35‐cm epicardial lead trajectories exhibiting different degrees of coupling with MRI incident electric fields. Experiments in anthropomorphic phantoms implanted with commercial cardiac implantable electronic devices confirmed the findings. Both electromagnetic simulations and experimental measurements were performed using head‐first and feet‐first positioning and various landmarks. Transfer function approach was used to assess the performance of suggested modifications in realistic body models.ResultsSimulations (head‐first, chest landmark) of a 35‐cm epicardial lead with a trajectory where the excess length of the lead was looped and placed on the inferior surface of the heart showed an 87‐fold reduction in the 0.1 g–averaged specific absorption rate compared with the lead where the excess length was looped on the anterior surface. Repeated experiments with a commercial epicardial device confirmed this. For fully implanted systems following low–specific absorption rate trajectories, there was a 16‐fold reduction in the average temperature rise and a 28‐fold reduction for abandoned leads. The transfer function method predicted a 7‐fold reduction in the RF heating in 336 realistic scenarios.ConclusionSurgical modification of epicardial lead trajectory can substantially reduce RF heating at 1.5 T, with benefits extending to abandoned leads.

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Section: Discussionmentioning

confidence: 99%

Modifying the trajectory of epicardial leads can substantially reduce MRI‐induced RF heating in pediatric patients with a cardiac implantable electronic device at 1.5T

Jiang,

Bhusal,

Nguyen

et al. 2023

Magnetic Resonance in Med

View full text Add to dashboard Cite

show abstract

“…Efforts to make MRI accessible to patients with conductive implants have a long history, as is clear from the spate of patents published in the past two decades (27)(28)(29)(30)(31)(32)(33)(34)(35)(36). Most of the work has focused on modifying the implant itself, e.g., in the case of active implants by increasing the lead's impedance or altering the material to reduce induced RF currents (36)(37)(38)(39). This has had limited success, and the restrictions on MRI remain.…”

Section: Discussionmentioning

confidence: 99%

Modifying the trajectory of epicardial leads can substantially reduce MRI-induced RF heating in pediatric patients with a cardiac implantable electronic device

Jiang

Bhusal

Nguyen

et al. 2022

Preprint

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Purpose: Infants and children with congenital heart defects, inherited arrhythmia syndromes, and congenital cardiac conduction disorders often receive epicardial implantable electronic devices. Unfortunately, once an epicardial device is implanted, the patient is no longer eligible to receive MRI exams due to an elevated risk of RF heating. Here we show that a simple modification in the trajectory of epicardial leads can substantially and reliably reduce RF heating during MRI at 1.5 T, with benefits extending to abandoned leads. Methods: Electromagnetic simulations were performed to assess RF heating of two common epicardial lead trajectories exhibiting different degrees of coupling with MRI incident electric fields. Experiments in anthropomorphic phantoms implanted with commercial cardiac implantable electronic devices (CIEDs) confirmed the findings. Results: Simulations of an epicardial lead with a trajectory where the excess length of the lead was looped and placed on the anterior surface of the heart showed a 9-fold reduction in 0.1g-averaged SAR compared to the lead with excess length looped on the inferior surface of the heart. Repeated experiments with a commercial epicardial device confirmed the results, showing a 16-fold reduction in the average temperature rise for fully implanted systems with leads following low-SAR trajectories, and a 20-fold reduction in RF heating on an abandoned lead. Conclusion: Surgical modification of epicardial lead trajectory can substantially reduce RF heating at 1.5 T, with benefits extending to abandoned leads.

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“…The past few years have witnessed a spike in efforts to alleviate the problem of MRI‐induced implant heating. The majority of works have been focused on modification of implant’s geometry, structure, or material . Despite a spate of patents filed over the past 2 decades, however, there is not a single MR‐safe DBS product available in the market, attesting to the fact that the problem of RF safety cannot be addressed by device manufacturers alone.…”

Section: Discussionmentioning

confidence: 99%

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

Golestanirad

Kazemivalipour

Lampman

et al. 2019

Magnetic Resonance in Med

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Purpose Patients with deep brain stimulation (DBS) implants benefit highly from MRI, however, access to MRI is restricted for these patients because of 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. Methods We performed finite element electromagnetic simulations to calculate specific absorption rate (SAR) at tips of DBS leads during MRI in a commercially available 1.2T vertical coil compared to a 1.5T horizontal scanner. Both isolated leads and fully implanted systems were included. Results We found 10‐ to 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. Conclusions If 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.

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Reducing RF-induced Heating near Implanted Leads through High-Dielectric Capacitive Bleeding of Current (CBLOC)

Cited by 5 publications

References 51 publications

Modifying the trajectory of epicardial leads can substantially reduce MRI‐induced RF heating in pediatric patients with a cardiac implantable electronic device at 1.5T

Modifying the trajectory of epicardial leads can substantially reduce MRI‐induced RF heating in pediatric patients with a cardiac implantable electronic device at 1.5T

Modifying the trajectory of epicardial leads can substantially reduce MRI-induced RF heating in pediatric patients with a cardiac implantable electronic device

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

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