Magnetic Resonance Imaging at 1.5 T After Cochlear Implantation

Crane, Benjamin T.; Gottschalk, Barbara; Kraut, Michael A.; Aygün, Nafi; Niparko, John K.

doi:10.1097/mao.0b013e3181ec1d61

Cited by 113 publications

(104 citation statements)

References 16 publications

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“…The operation can be performed with a small incision in the skin under local anesthesia. Explantation of the internal magnet and reimplantation after MRI were to be performed on the same day to keep the risk of infection as low as pos- sible [15,16]. In the present collective, this method was performed in 8 cases among 2027 CI operations in the period between 2004 and 2009 and resulted in 34.8 % of all magnet revision surgeries.…”

mentioning

confidence: 92%

“…In relation to special implant types, multiple in vitro and in vivo studies were able to show that MRI examinations can be performed safely if the magnet remains in the silicone pocket. However, special implant-dependent precautions must be taken: For example, no field strengths above 1.5T; use of a compression head bandage; prior comprehensive patient counseling [7,15,16,18]. In the case of an indicated MRI examination, this bandage technique was used without prior explantation of the internal magnet starting in 2009 at our clinic, provided that the particular CI system was approved.…”

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confidence: 99%

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Magnet Dislocation: An Increasing and Serious Complication Following MRI in Patients with Cochlear Implants

Hassepaß

Stabenau

Arndt

et al. 2014

Fortschr Röntgenstr

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Purpose: Cochlear implantation (CI) represents the gold standard in the treatment of children born deaf and postlingually deafened adults. Initial magnetic resonance imaging (MRI) was contraindicated in CI users. Meanwhile, there are specific recommendations concerning MRI compatibility depending on the type of CI system and the device manufacturer. Some CI systems are even approved for MRI with the internal magnet left in place. The aim of this study was to analyze all magnet revision surgeries in CI patients at one CI center and the relationship to MRI scans over time. Materials and Methods: Between 2000 and 2013, a total of 2027 CIs were implanted. The number of magnet dislocation (MD) surgeries and their causes was assessed retrospectively. Results: In total 12 cases of MD resulting from an MRI scan (0.59?%) were observed, accounting for 52.2?% of all magnetic revision surgeries. As per the labeling, it was considered safe to leave the internal magnet in place during MRI while following specific manufacturer recommendations: MRI intensity of 1.5 Tesla (T) and compression head bandage during examination. Conclusion: A compression head bandage in a 1.5?T MRI unit does not safely prevent MD and the related serious complications in CI recipients. We recommend a Stenvers view radiograph after MRI with the internal magnet in place for early identification of MD, at least in the case of pain during or after MRI examination. MRI in CI patients should be indicated with restraint and patients should be explicitly informed about the possible risks. Recommendations regarding MRI compatibility and the handling of CI patients issued with MRI for the most common CI systems are summarized. Key Points: ??MRI in CI patients: manufacturer recommendations must be followed. ??Magnet dislocation due to MRI is a serious complication. ??In case of suspected magnet dislocation: Use Stenvers view radiograph for diagnosis. ??Instant presentation to a CI center is mandatory for proper management of dislocation. ??Immediate CI revision surgery must be performed in the case of magnet dislocation. Citation Format: ??Hassepass F, Stabenau V, Arndt S et?al. Magnet Dislocation: An Increasing and Serious Complication Following MRI in Patients with Cochlear Implants. Fortschr R?ntgenstr 2014; 186: 680???685

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mentioning

confidence: 92%

mentioning

confidence: 99%

Magnet Dislocation: An Increasing and Serious Complication Following MRI in Patients with Cochlear Implants

Hassepaß

Stabenau

Arndt

et al. 2014

Fortschr Röntgenstr

View full text Add to dashboard Cite

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“…On the one hand, there are large artifacts on the MRI when the magnet is not removed and only a bandage is used during the imaging studies [3] . Crane et al [3] found that the CI generally produced an artifact on brain MRIs, with a mean maximal anterior-posterior dimension of 6.6 cm and a lateral dimension of 4.8 cm around the site of the device. They reported that the contralateral internal auditory canal was visualized in all of their 16 patients, and that the ipsilateral internal auditory canal was at least party visible in all but 1 patient.…”

Section: Discussionmentioning

confidence: 99%

“…They concluded that surgical removal of the internal magnet before scanning with the 1.5-Tesla MRI may not be necessary if a compression dressing is applied. However, there are no exact data on the number and outcome of CI recipients who had already undergone MRI studies with and without removing the CI internal magnet, so the controversy over the necessity of its removal remains unresolved [3,4] . This is the first paper describing the surgical procedure of magnet removal with subsequent reinsertion in a CI recipient who underwent an MRI.…”

Section: Introductionmentioning

confidence: 99%

Magnet Removal and Reinsertion in a Cochlear Implant Recipient Undergoing Brain MRI

Migirov¹,

Wolf²

2013

ORL

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Background: Recent advances in cochlear implants (CIs) and in magnetic resonance imaging (MRI) techniques have led to increasing numbers of implanted patients who have undergone brain MRIs for various reasons. This paper first describes the surgical procedure for removing the magnet before an MRI and its subsequent reinsertion immediately afterwards in a CI recipient. Method: After the administration of local anesthesia, the magnet was removed by a surgical incision made along the posterior margin of the receiver-stimulator. The flap was elevated and the capsule over the implant was incised. The magnet was removed, maintained under sterile conditions and reinserted immediately after the completion of the 1.5-Tesla MRI. Results: The patient was able to wear her device immediately after surgery. Large CI-associated artifacts were observed on the MRIs irrespective of sequences. The function of the device was not altered by either the MRI or the surgical procedure. Conclusion: The proposed surgical incision that follows the posterior margins of the receiver-stimulator allows the wearing of the device immediately after the surgical procedure. An MRI has limited diagnostic value for lesions located on the implanted side due to unavoidable artifacts, even after the magnet has been removed.

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“…[26][27][28] There are several other implanted devices that are more controversial, including vagal nerve stimulators 29 and cochlear implants. 30 The most important intervention the anesthesiologist can make is to have conversations with the institutional MRI safety officer prior to scheduling patients with questionable implantable devices in an ioMRI suite.…”

Section: Patient Concernsmentioning

confidence: 99%

Anesthetic Concerns for Patients Undergoing Neurosurgical Procedures Utilizing Intra-operative Magnetic Resonance Imaging

McClain¹,

Chimbira²

2014

US Neurology

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61Modern anesthetic practice requires the anesthesiologist to care for extremely sick patients while negotiating the intricacies of myriad procedural environments. One such unique environment that is becoming increasingly important for contemporary anesthesiologists to be familiar with is that of the intra-operative magnetic resonance imaging (ioMRI) suite. 1,2 ioMRI is an evolving technology that offers precise intra-cranial lesion localization and intra-operative navigation by combining the highresolution imaging capabilities of MRI with an operative suite. When ioMRI is combined with other, more conventional, intra-operative navigation strategies, it has the ability to provide increased precision of navigation and aid in resection of a variety of intra-cranial lesions. [3][4][5][6] There are a number of important considerations when caring for patients in this environment that are quite different from any other perioperative environment.7 As these types of operative suites proliferate, it is becoming increasingly important for anesthesiologists to become familiar with the unique aspects of delivering safe, effective perioperative care for patients undergoing ioMRI-guided neurosurgical procedures. This review will discuss considerations when caring for patients in an ioMRI suite. HistoryioMRI was developed in the 1990s in an attempt to improve intra-operative navigation and have a real-time assessment of the extent of resection during intra-cranial neurosurgical procedures. 8 Prior to the development of ioMRI, a variety of stereotactic navigational systems had been utilized to improve localization and precision of resection. These techniques employed either frame-based or frameless systems. All these systems involved triangulating a number of points over multiplanar images of the head acquired preoperatively. AbstractIntra-operative magnetic resonance imaging (ioMRI) is an evolving technology that offers precise intra-cranial lesion localization and intra-operative navigation by combining the high-resolution imaging capabilities of MRI with an operative suite. Developed in the 1990s, ioMRI presents caregivers with a variety of unique challenges revolving around performing surgical procedures in an operating theatre with a high-strength magnetic field.Different types of ioMRI systems exist, differentiated by the relative mobility of the patient and magnet. As with any MRI environment, safety is of paramount concern. Published safety guidelines exist from both the American College of Radiology and the American Society of Anesthesiologists.A variety of checklists can be used to enhance the safety of the ioMRI suite. There are a variety of anesthetic considerations when caring for patients in this environment including concerns related to the anesthesia equipment, the patient, and the general MRI environment. A multidisciplinary approach can encourage safety and efficiency in this unique operating room. The purpose of this review is to discuss the variety of topics that anesthesiologists need to consider using thi...

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Magnetic Resonance Imaging at 1.5 T After Cochlear Implantation

Abstract: Patients can safely undergo 1.5 T MRI after CI if the device is tightly bound before scanning. Magnet displacement was not observed, and we think the risk to be minimal compared with the risk and inconvenience of removing the magnet before the study.

Cited by 113 publications

References 16 publications

Magnet Dislocation: An Increasing and Serious Complication Following MRI in Patients with Cochlear Implants

Magnet Dislocation: An Increasing and Serious Complication Following MRI in Patients with Cochlear Implants

Magnet Removal and Reinsertion in a Cochlear Implant Recipient Undergoing Brain MRI

Anesthetic Concerns for Patients Undergoing Neurosurgical Procedures Utilizing Intra-operative Magnetic Resonance Imaging

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