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Introduction: Cochlear implantation in patients with Ménière's disease (MD) is the treatment of choice in cases of functional deafness. Additional vertigo control is of central importance in this group of patients. Endolymphatic hydrops (ELH) is the pathophysiological correlate of MD and can be evaluated by magnet resonance imaging (MRI). Bilateral MD occurs in 10–33% and can be the reason for a postoperative persisting or newly occurring vertigo in this group. Recent developments in the field of implant magnets and experience in MRI sequences allow the diagnostic performance of MRI in cochlear implantees to be evaluated. The aim of the present study was to evaluate the possibility of MRI as a visual diagnostic tool for endolymphatic hydrops in cochlear implantees. Material and Methods: This was a retrospective study including three cochlear implantees (age: 61–76 years, one female, two male) suffering from MD who, postoperatively, had a recurrence of vertigo with Ménière's-like symptoms. An MRI was performed for the evaluation of ELH (ELH-MRI). MRI observation was performed by a 4 h iv. delayed Gad 3 D Flair sequence. Results: In all cases, the ipsilateral implant magnet artifact covered the vestibulum, the semicircular canals and the cochlea. The contralateral vestibulum, the semicircular canal and the cochlea were fully observable, and a classification of the ELH-MRI could be performed. Conclusion: ELH-MRI scanning allows for the detection of contralateral labyrinthine endolymphatic hydrops and is a tool for the postoperative evaluation of vertigo in cochlear implantees. [ABSTRACT FROM AUTHOR]

Introduction Cochlear implant (CI) magnets and surgical techniques (e.g., positioning) have made an impact on the relationship between CI and magnetic resonance imaging (MRI) by solving the problem of pain and artifact. Recent investigations displayed the possibility to evaluate the CI electrode position by MRI in vivo. However, further improved perceptual quality is needed to allow an improved evaluation of the electrode. Aims The aim of this study was to assess a cochlear model for the examination of CI electrode pattern and MRI sequences in vitro. Materials and Methods We investigated CI electrodes in a fluid-filled three-dimensional artificial scala tympani model combined with a fluid package in a 3T MRI scanner. Different high-resolution T2 sequences (0.6–0.2 mm voxel size) were used for the visual electrode pattern evaluation for finding an optimized sequence. Results Artificial models can be used to evaluate MRI characteristics of CI electrodes. In our scanner configuration, a 0.3 mm voxel and 0.9 mm slice thickness sequence showed the best compromise between resolution and scanning time. Conclusion and Significance MRI model-based testing can be performed in vitro to evaluate CI electrodes' pattern and to optimize sequences. An MRI model is a tool for in vitro testing of MRI sequences and might help for future in vivo applications. [ABSTRACT FROM AUTHOR]

BACKGROUND: In cochlear implant recipients, the diagnostic value of magnetic resonance imaging (MRI) scans is reduced by image artifacts. The static magnetic field of a 3.0T scanner is associated with the risk of implant demagnetization. The development of rotatable implant magnets aimed to support the advancement of 3.0T MRI scanners and eliminate the risk of demagnetization of cochlear implant magnets. This study aimed to compare the image artifacts caused by first-t and second-generation rotatable cochlear implant magnets in 3.0T MRI. METHODS: Three Tesla MRI T2W TSE sequences were performed on 3 subjects with first- and second-generation rotatable cochlear implant magnets. The cochlear implant was fixed to the head at the implantation position by a swim cap. The size of the image artifact was determined in the transverse plane. RESULTS: Intraindividual comparative analyses showed that within the margin of combined uncertainty of 5 mm at a resolution of 2 mm, the cochlear implant-induced image artifacts in all subjects showed for both (first- and second-generation rotatable cochlear implant magnets), the same maximum image artifact dimension of 125 mm. CONCLUSION: We could show that no difference in image artifact size was detected within the margin of error determined by resolution, localized induced shift of the scan, and reproducibility of the tilt angle of the head relative to the chest in a living subject. Assumed improved magnet attachment can be reached without compromising of the magnet artifact size. [ABSTRACT FROM AUTHOR]

Background: The combination of intralabyrinthine schwannoma (ILS) removal and cochlear implantation is the standard of care after surgical resection for audiological rehabilitation. Intracochlear ILS is not only the most frequent tumor in this group of schwannomas, but it is also, to some degree, surgically the most challenging because of its position behind the modiolus. Recent developments in the knowledge of implant position, implant magnet choice, and magnetic resonance imaging (MRI) sequences make an MRI follow-up after surgical removal possible. Thus far, no results are known about the surgical success and residual rate of these kind of tumors. The aim of the present study was to perform an early MRI follow-up for the evaluation of residual or recurrent intracochlear ILS after surgical removal and cochlear implantation. Methods: In a retrospective study, we evaluated seven patients after an intracochlear ILS removal and single-stage cochlear implantation with a mean period of 13.4 months post surgery with a 3T T1 GAD 2 mm sequence for a residual ILS. Patients were operated on using an individualized technique concept. Results: In six out of seven cases, 3 T T1 GAD 2 mm MRI follow-up showed no residual or recurrent tumor. In one case, a T1 signal indicated a tumor of the upper inner auditory canal (IAC) at the MRI follow up. Conclusion: MRI follow-up as a quality control tool after ILS removal and cochlear implantation is highly important to exclude residual tumors. Long-term MRI evaluation results are needed and can be obtained under consideration of implant position, implant magnet, and MRI sequence choice. A preoperative MRI slice thickness less than 2 mm can be recommended to visualize possible modiolar and IAC expansion. [ABSTRACT FROM AUTHOR]