Effect of Implant Position on Magnetic Resonance Image Distortion

The Effect of Changes in Head Position on Magnetic Resonance Image Distortion in Patients With Auditory Implants

Patients with Neurofibromatosis type 2 (NF2) almost always develop acoustic neuromas in both ears. As a result of the tumours themselves or the treatment of the tumours, many patients become profoundly deaf in both ears. It is possible to restore a degree of hearing by placing a hearing implant in the brainstem adjacent to the hearing pathways within the brain. This is termed an auditory brainstem implant (ABI).

The aim of this study is to find the optimum head position in relation to the MRI magnet field, which would produce least area of image distortion in patients with ABIs. This will be of benefit in optimising the MR imaging in future patients with implants.

Study Overview

• Status: Completed
• Conditions: Neurofibromatosis Type 2
• Intervention / Treatment: Device: MR imaging

Detailed Description

Auditory brainstem implants (ABI) are placed against the auditory centres in the brainstem if it is not possible to implant the cochlea or if the cochlear nerve, which conveys neural signals from the cochlea to the brainstem, is damaged or absent. The latter device is usually used in patients with Neurofibromatosis type 2 (NF2) who develop bilateral benign inner ear tumours called vestibular schwannomas as well as other neurological tumours1. These patients often become bilaterally profoundly deaf either as a result of the disease or because of surgery to remove the tumours and require an ABI.

Patients with NF2 require monitoring of their tumours. In the absence of an auditory implant it is possible to use magnetic resonance imaging. This is the gold standard imaging technique as it gives excellent views of the soft tissues of head. However, there has been concern regarding the use of MRI in patients with auditory implants until recently because of potential problems such as demagnetisation of the magnet within the implant, implant magnet displacement and risk to the integrity of the implant electronics. In addition, the magnet field of the implant magnet results in imaging artefact (manifesting as a signal void) around the implant site that limits the information that can be obtained.

• Study Type: Interventional
• Enrollment (Actual): 5
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United Kingdom
  • Manchester (Manchester Borough)
    • Manchester, Manchester (Manchester Borough), United Kingdom, M13 9WL
      • Central Manchester University Hospitals NHS Foundation Trust

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

- Any patient over the age of 18 with NF2 who has an auditory implant (cochlear or auditory brainstem implant) in situ and requires MRI scanning.

Exclusion Criteria:

Children under the age of 18 years Claustrophobia Bilateral implants

Contraindications and relative contraindications for MRI (as per the Radiology Department MRI protocol) including:

Pacemaker Certain metallic heart valves Ferromagnetic implanted materials and foreign bodies

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: NF2 who has an auditory implant	Device: MR imaging

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
To study the effect of magnet orientation in auditory brainstem implants/ cochlear implants in determining the size of signal void seen on MRI scanning.	1 year

Secondary Outcome Measures

Outcome Measure	Time Frame
To identify if there is an angle at which the signal void is minimised	1 year

Collaborators and Investigators

• Sponsor: Manchester University NHS Foundation Trust
• Investigators: Principal Investigator: Simon Lloyd, Manchester University NHS Foundation Trust

Study record dates

Study Major Dates

• Study Start (Actual): February 3, 2014
• Primary Completion (Actual): January 31, 2015
• Study Completion (Actual): January 31, 2015

Study Registration Dates

• First Submitted: September 18, 2014
• First Submitted That Met QC Criteria: September 18, 2014
• First Posted (Estimate): September 22, 2014

Study Record Updates

• Last Update Posted (Actual): March 17, 2020
• Last Update Submitted That Met QC Criteria: March 16, 2020
• Last Verified: March 1, 2020

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Nervous System Diseases; Neoplasms by Histologic Type; Neoplasms; Genetic Diseases, Inborn; Neuromuscular Diseases; Otorhinolaryngologic Neoplasms; Otorhinolaryngologic Diseases; Neurodegenerative Diseases; Neuroectodermal Tumors; Neoplasms, Germ Cell and Embryonal; Neoplasms, Nerve Tissue; Peripheral Nervous System Diseases; Ear Diseases; Nervous System Neoplasms; Heredodegenerative Disorders, Nervous System; Neoplastic Syndromes, Hereditary; Cranial Nerve Diseases; Neuroendocrine Tumors; Nerve Sheath Neoplasms; Neurocutaneous Syndromes; Peripheral Nervous System Neoplasms; Cranial Nerve Neoplasms; Neuroma, Acoustic; Neurilemmoma; Neuroma; Vestibulocochlear Nerve Diseases; Retrocochlear Diseases; Neurofibromatoses; Neurofibromatosis 1; Neurofibroma; Neurofibromatosis 2
• Other Study ID Numbers: R01623