Magnetic Resonance Imaging of Cochlear Implant Recipients

Young, Nancy M.; Rojas, Carin; Deng, Jie; Burrowes, Delilah; Ryan, Maura E.

doi:10.1097/mao.0000000000001053

Cited by 29 publications

(30 citation statements)

References 14 publications

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“…One of the limitations in this MRI‐predominant protocol is the inability to predict cases that are challenging intraoperatively due to sclerotic mastoids and poor middle ear aeration but demonstrate otherwise normal anatomy on MRI due to inferior sensitivity in demonstrating bony landmarks as compared to HRCT . This occurred in only two of the 218 (0.09%) cases.…”

Section: Discussionmentioning

confidence: 99%

“…This occurred in only two of the 218 (0.09%) cases. Although poor pneumatization can create a more challenging mastoidectomy, it rarely results in a fundamentally different surgical approach, impossible mastoidectomy, or aborted CI . Certainly, prior knowledge of the degree of poorly pneumatized bone may have been an asset in these challenging intraoperative encounters; however, both surgeries proceeded with the fundamentally identical approach and resulted in successful CI.…”

Section: Discussionmentioning

confidence: 99%

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Efficacy of a selective imaging paradigm prior to pediatric cochlear implantation

et al. 2019

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Objectives/Hypothesis: There is no consensus on the necessary preoperative imaging in children being evaluated for cochlear implantation (CI). Dual-imaging protocols that implement both magnetic resonance imaging (MRI) and high resolution computed tomography (HRCT) create diagnostic redundancy in the face of potentially unnecessary radiation and anaesthetic exposure. The objectives of the current study were to examine the efficacy of an MRI-predominant with selective HRCT imaging protocol.Study Design: Retrospective review. Methods: The protocol was implemented over a 4-year period, during which HRCT was obtained in addition to MRI only if specific risk factors on clinical assessment were identified or if imaging findings in need of further evaluation were detected on initial MRI evaluation. Retrospective review of operative reports and prospective review of imaging were performed; anesthetic exposure and costing information were also obtained.Results: Of the 240 patients who underwent assessment, seven (2.9%) had combined HRCT and MRI performed concurrently based on initial clinical assessment, 15 (6.3%) underwent HRCT based on imaging anomalies found on MRI, and MRI alone was ordered for the remaining 218 (90.1%). All patients were implanted without complication. Overall, radiation exposure, general anesthesia (GA), and healthcare costs were reduced.Conclusions: MRI alone can be used in the vast majority of cases for preoperative evaluation of pediatric CI candidates resulting in a significant reduction in healthcare costs, radiation, and GA exposure in children. The additional need for HRCT occurs in a small proportion and can be predicted up front on clinical assessment or on initial MRI.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Efficacy of a selective imaging paradigm prior to pediatric cochlear implantation

et al. 2019

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“…Despite the precautions specified in the MR Conditional labeling, surgical revision occasionally is required after completion of the MR imaging examination to correct magnet displacement (1,7,8). If the internal magnet has been removed and replaced multiple times, the silicone flange that secures the magnet may become compromised or fatigued, and the magnet may be more likely to displace or flip from its designated position when approaching the static magnetic field of the MR imaging unit.…”

Section: Teaching Pointsmentioning

confidence: 99%

MR Imaging and Cochlear Implants with Retained Internal Magnets: Reducing Artifacts near Highly Inhomogeneous Magnetic Fields

et al. 2018

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The number of patients receiving cochlear implants and auditory brainstem implants for severe to profound sensorineural hearing loss has rapidly increased. These implants consist of an internal component implanted between the skull and the temporal scalp and an external removable speech processor unit. A small magnet within the internal component is commonly used to hold the external speech processor unit in place. Several cochlear implant models have recently received U.S. Food and Drug Administration and European Economic Area regulatory approval to allow magnetic resonance (MR) imaging examinations to be performed under certain specified conditions. The small internal magnet presents a challenge for imaging of the head and neck near the implant, creating a nonlinear magnetic field inhomogeneity and significant MR imaging artifacts. Fat-saturation failures and susceptibility artifacts severely degrade image quality. Typical artifacts at diffusion-weighted imaging and accelerated imaging are exacerbated. Each examination may require impromptu adjustments to allow visualization of the tissue or contrast of interest. Patients may also be quite uncomfortable during the examination, as a result of either imposed magnetic forces or a tight head wrap that is often applied to minimize internal magnet movement. Translational forces and torque sometimes displace the implanted magnet even when a head wrap is used. Diseases such as neurofibromatosis type 2 that are associated with bilateral vestibular schwannomas and hearing loss often require lifelong tumor surveillance with MR imaging. A collaborative team of radiologists, technologists, and/or medical physicists or MR imaging scientists, armed with strategies to mitigate artifacts near implanted magnets, can customize the examination for better visualization of tissue and consistent comparison examinations over time. RSNA, 2018.

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“…The internal components of currently marketed devices with the internal magnet in place are MR Conditional at 1.5T as long as patients are given some variation of compression wrap and splint for their head. There are reported cases of dislocation or tilting of the internal magnet despite the compressive bandage, although patients with Oticon Medical's Neuro Zti have been scanned at 1.5T with no AEs, with or without head wrap . Caution should be used when a patient presents with an older model, as some that are no longer marketed in North America, including Cochlear's CI22M, Advance Bionics CLARION, and HiResolution 90K series, have different MRI safety guidelines.…”

Section: Discussionmentioning

confidence: 99%

“…No compressive wrap is needed, as it has a rotatable and diametrically magnetized internal magnet which should prevent its dislocation. No AEs have been reported for patients with SYNCHRONY when scanned at 3T …”

Section: Discussionmentioning

confidence: 99%

MRI safety and devices: An update and expert consensus

Maralani

Schieda

Hecht

et al. 2019

Magnetic Resonance Imaging

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The use of magnetic resonance imaging (MRI) is increasing globally, and MRI safety issues regarding medical devices, which are constantly being developed or upgraded, represent an ongoing challenge for MRI personnel. To assist the MRI community, a panel of 10 radiologists with expertise in MRI safety from nine high‐volume academic centers formed, with the objective of providing clarity on some of the MRI safety issues for the 10 most frequently questioned devices. Ten device categories were identified. The panel reviewed the literature, including key MRI safety issues regarding screening and adverse event reports, in addition to the manufacturer's Instructions For Use. Using a Delphi‐inspired method, 36 practical recommendations were generated with 100% consensus that can aid the clinical MRI community. Level of Evidence: 5 Technical Efficacy Stage: 5 J. Magn. Reson. Imaging 2020;51:657–674.

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Magnetic Resonance Imaging of Cochlear Implant Recipients

Cited by 29 publications

References 14 publications

Efficacy of a selective imaging paradigm prior to pediatric cochlear implantation

Efficacy of a selective imaging paradigm prior to pediatric cochlear implantation

MR Imaging and Cochlear Implants with Retained Internal Magnets: Reducing Artifacts near Highly Inhomogeneous Magnetic Fields

MRI safety and devices: An update and expert consensus

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