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Background: When performing magnetic resonance imaging (MRI) in patients with a cochlear implant (CI), complication rates vary widely in the literature. The primary objective of this retrospective study was to determine the prevalence of complications, in particular magnet dislocation, in patients with CI undergoing 1.5 Tesla (T) MRI. As a secondary objective, the prevalence of magnet dislocation for specific cochlear implant device types was elaborated.
Methods: In a single-center retrospective study, all patients with a cochlear implant presenting for an MRI examination at 1.5 T at our institution between January 1st, 2010 and December 31st, 2020 were included. Implants with axial and diametrical magnets were included in the study. MRI safety measures were applied before imaging. The prevalence of complications was evaluated. Magnet dislocation rates were calculated for device types with at least 20 MRI exposures.
Results: During the study period, 196 MRI examinations were performed in a total of 128 patients, accounting for 149 different implants (21 implanted bilaterally) with a total of 231 implant exposures to MRI (average 1.69 ± 1.57; min. 1, max. 12). Complications were reported in 50 out of 231 cochlear implant exposures (21.6%). Magnet dislocation occurred in a total of 27 cases (11.7%). Dislocation rates were 29.6% for the Cochlear® CI500 series (24 dislocations from 81 exposures), 1.1% for the Cochlear® CI24RE series (1 from 87) and 0% for the MED-EL® Synchrony (0 from 36). The dislocation rate for the CI500 was significantly higher than for the CI24RE (χ = 26.86; p < 0.001; ϕ = 0.40) or the Synchrony (χ = 13.42; p < 0.001; ϕ = 0.34).
Conclusions: For 1.5 T MRI, the risk of magnet dislocation ranges from 0 to 29.6% and depends on the CI device type. Implants with a diametrical magnet can be considered potentially MRI-safe, whereas in CIs with axial magnets, the CI500 is at high risk of magnet dislocation. Therefore, apart from a strict indication for an MRI and adherence to safety protocols, post-MRI follow-up examination to rule out magnet dislocation is recommended.
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http://dx.doi.org/10.1186/s40463-023-00633-w | DOI Listing |
Eur J Orthop Surg Traumatol
September 2025
Department of Orthopedics, Shanghai Changzheng Hospital, Shanghai, China.
Purpose: To investigate the images and treatment differences for Type IIIa atlantoaxial rotary dislocation (AARD) by comparing the imaging characteristics of patients with Type III and Type IIIa AARD.
Methods: The present study retrospectively analyzed a cohort of 35 patients who underwent posterior C1-C2 intra-articular fusion due to AARD from our hospital database. Among them, 23 patients were diagnosed with Type III AARD, while the remaining 12 patients were diagnosed with Type IIIa AARD.
Nanoscale
September 2025
St. Petersburg State University, 199034 St. Petersburg, Russia.
Using angle-resolved photoemission spectroscopy (ARPES) with spin resolution, scanning tunneling microscopy/spectroscopy (STM/STS) and density functional theory (DFT) methods, we study the electronic structure of graphene-covered and bare Au/Co(0001) systems and reveal intriguing features, arising from the ferrimagnetic order in graphene and the underlying gold monolayer. In particular, a spin-polarized Dirac-cone-like state, intrinsically related to the induced magnetization of Au, was discovered at point. We have obtained a good agreement between experiment and theory for bare and graphene-covered Au/Co(0001) and have proven that both Au ferrimagnetism and the Dirac-cone-like band are intimately linked to the triangular loop dislocations present at the Au/Co interface.
View Article and Find Full Text PDFPurpose: The primary purpose was to assess sulcus angle (SA) magnetic resonance imaging (MRI) measurements and determine diagnostic cutoff values along four axial levels on cartilaginous and osseous surfaces comparing those with patellar dislocations (PD) versus controls. A secondary aim was to identify differences in SA between patients with one-time dislocation (OTD) versus recurrent patellar dislocations (RPDs).
Methods: Paediatric patients with a history of PD were retrospectively grouped into those with an OTD versus RPDs.
Eur Radiol
September 2025
Department of Radiology, Bilkent City Hospital, Ankara, Turkey.
Objective: To compare tibial tubercle-trochlear groove (TT-TG) and tibial tubercle-Roman arch (TT-RA) distances in patients with patellar dislocation or subluxation, evaluate TT-RA reliability and reproducibility, and determine pathological threshold values for surgical treatment using magnetic resonance imaging (MRI) and computed tomography (CT).
Materials And Methods: Retrospective analysis included 259 patient and 262 control examinations of knee MRIs and/or CTs performed. TT-RA, TT-TG, and tibial tubercle-posterior cruciate ligament (TT-PCL) distances, Roman Arch height, trochlear sulcus angle, and total femoral condyle width were measured by two radiologists, and trochlear morphology was assessed.
Knee Surg Sports Traumatol Arthrosc
September 2025
Division of Orthopaedics and Traumatology, Cantonal Hospital Winterthur, Winterthur, Switzerland.
Purpose: Patellofemoral instability is a common knee condition and often associated with trochlear dysplasia. Sulcus-deepening trochleoplasty is a surgical option to reshape the trochlear groove and stabilise the patella. Although this procedure is considered safe and effective, the development of postoperative patellofemoral chondral lesions remains a topic of concern.
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