Cochlear Implants and MRI · ©2017 MFMER | slide-1 Cochlear Implants and MRI: Experience with over...
Transcript of Cochlear Implants and MRI · ©2017 MFMER | slide-1 Cochlear Implants and MRI: Experience with over...
©2017 MFMER | slide-1
Cochlear Implants and MRI:Experience with over 100 studies performed with magnets in place
Neil S. Patel, MDFellow – Neurotology
Department of OtorhinolaryngologyMayo Clinic, Rochester, MN
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No financial disclosures
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100 MRIs performedper 1000 people in US
Increased accessand utilization of CI
Treatment paradigmthat facilitates CI over ABI
NF2
2013-2019:Emergence of 3.0Tcompatible devices
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79Patients Total Studies Performed
NF2131
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Headwrap Protocol1. 2” x 2” unaltered thermoplastic square (i.e. Aquaplast)
placed over receiver stimulator2. 1 layer of foam tape (i.e. 3M Microfoam)3. Several layers of gauze wrap (i.e. Kerlix)4. 1 layer of self-adherent tape dressing (i.e. Coban)5. Initially injected 2% lidocaine around receiver stimulator,
now often perform headwrap without local anesthesia
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ResultsN (%) or Median (IQR)
PatientsAgeMalesNF2Age < 18Device type documented
”MRI compatible magnet”
79 (100)62 (45-73)
55 (70)12 (15)3 (4)
75 (96)16 (21)
Total MRI studies“Study-ears”: accounts for bilateral CI or CI/ABI combinations
Cochlear ABICochlear CIMED-EL SynchronyAdvanced Bionics 3D
131154
14 (9)82 (53)42 (27)1 (0.6)
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Results
N (% of studies)
Adverse EventsMagnet tilt requiring manual repositioningMagnet displacement requiring OR repositioningPain
Pain that required discontinuation of examination
18 (14)7 (5)7 (5)4 (3)3 (2)
Total studies 131 (100)
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CI 522
Have implantedseveral CI622 recently,no MRIs yet
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Advanced Bionics Ultra3D
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MED-EL Synchrony
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Discussion• Carlson 2015
• 34 studies• 3 (9%) magnet tilt, 2 (6%) displacement requiring OR
• Present study (includes 2015-2018)• 131 studies• 7 (5%) magnet tilt, 7 (5%) displacement requiring OR
• Now headwrap performed by radiology• Specific SAR (specific absorption rate) limitations defined by
manufacturers under the supervision of an MRI physicist
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Magnet Displacement• S/Sx of magnet tilt/displacement
• Pain during exam / after exam is complete
• Palpable “bump”• Inability to retain processor• Late: skin erythema,
breakdown/exposure• Diagnosis
• Clinical exam: offers opportunity to manually re-seat magnet
• X-ray: cannot replace manual exam
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Conclusions• MRI is safe with TIGHT headwrap around
receiver stimulator
• Tilted magnet can be re-seated with pressure
• Remove and replace magnet for:• MR for radiosurgery planning• Artifact concerns
• Removal and replacement probably weakens silastic for removable magnets
• In spite of “MR conditional at 3.0T” devices, artifact may necessitate 1.5T study
Overall AE rate
Tilt/displacement
3% Pain
10%
14%
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Thank You