Complications of cochlear implants with MRI scans in different body regions: type, frequency and impact

Abstract

Objectives: The aim was to assess the type, frequency and impact of MRI-related complications in patients with cochlear implants (CI) and MRI indications in different body regions.

Methods: For that purpose, the institutional radiology database of a single tertiary hospital was searched for patients with a CI who underwent MRI between 2001 and 2018. The number of MRI examinations and complications were retrieved from the patient record. Examinations were categorized into five distinct body regions or combinations thereof. Records of CI artifacts in the head also included basic information on diagnostic image quality.

Results: Out of 1017 MRI database entries (examinations) of patients with a CI, 91 records were after implantation (71 patients) and 66 were attempted (no contraindications, 49 patients). In four cases (4/66, 6.1%), the magnet was dislocated and had to be replaced surgically. Three out of four severe complications occurred for examination regions outside the head. Thirteen MRI examinations were aborted due to pain (19.7%) and one because of artifacts-resulting in 48 scans (72.7%) completed successfully (36 patients). All cranial scans featured device artifacts in all sequences, but the majority of them did not affect proper imaging diagnostics in the respective region.

Conclusion: This retrospective, single-center analysis of patients with MRI-conditional cochlear implants shows that MRI-related complications were common, at least in models with a fixed magnet, despite appropriate precautions and compliance with the manufacturers' guidelines. MRI examinations of CI patients should therefore be indicated strictly until the exact causes have been clarified.

Keywords: Cochlea; Implant; MR complication; MR safety; MRI.

Fig. 1

Bar graph showing the number of scheduled MRI examinations with cochlea implant per year between 2001 and 2018 at a single tertiary center (three campuses). The stacked bar for 2018 shows both the actual number for the first 4 months (7, dark gray) and the extrapolated value (21, light gray) for the entire year

Fig. 2

Flowchart of patients with a cochlear implant (CI) and MRI examinations between 2001 and 2018 from a single tertiary center and breakdown into body regions for scans with the CI device

Fig. 3

Number of severe and mild MRI complications observed for 66 MRI scans of CI patients with an MR-conditional device

Fig. 4

Examples of transverse gradient-echo (GRE) MR images illustrating extent of CI artifact in a 53-year-old female patient to depict cochlear anatomy and vestibulocochlear nerve on the contralateral side a: T2-weighted FLAIR image (FOV 250 × 203 mm², slice thickness ST 3.0 mm, slice gap 0.6 mm), b T2/T1-weighted 3D CISS image, coherent balanced GRE using dual-excitation (FOV 180 × 180 mm², ST 0.6 mm), c contrast-enhanced T1-weighted fat-saturated VIBE image, spoiled 3D GRE with volume interpolation (FOV 160 × 180 mm², ST 1.0 mm)

Fig. 5

SOP diagram for MRI examinations with cochlear implants