Magnetic Resonance Imaging Evaluation of Inner Ear Pathology Using Intra-Tympanic Contrast Agent
This is a pilot study of patients with clinical symptoms of Ménière's disease using injection of diluted magnetic resonance imaging (MRI) contrast agent into the ear to evaluate inner ear structures.
The goal is to reproduce imaging findings described by non-United States (US) institutions, improve on image quality with decreased scan time and evaluate the dynamics of the contrast movement into the inner ear structures.
Participants will be scheduled for study sessions on 2 consecutive days to include consent, baseline audiometric evaluation, intra-tympanic contrast administration, serial MR imaging, and follow-up audiometry evaluation in the injected ear.
Participants over 59 years old or who have medical conditions will have a blood test to check kidney function to ensure they can safely receive the contrast.
Magnevist (gadopentetate dimeglumine, Bayer Health Care) will be diluted eightfold with sterile saline (1:7 v/v) in a 1 ml syringe and injected intra-tympanically with a 23-25g needle up to 0.4 ml or less if contrast reflux is noted under direct visualization. Anesthesia with topical phenol is available for this procedure.
Inclusion Criteria: Symptoms and clinical exam consistent with Ménière's disease Ability to undergo MR exam Interest in participating in this study Ability to provide informed consent Exclusion Criteria: Children (under age 18), Contraindication to MR imaging (see attached UCSD MR Screening Form) Claustrophobia precluding MR exam without sedation Contraindication to receiving intravenous gadolinium-based contrast agent (see attached UCSD Contrast Policy) Patients who are pregnant or breast feeding (intravenous contrast agents are Category C) Contraindication to osmotic challenge (congestive heart failure, renal failure, hepatic failure)
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The relative volume of the non-enhancing endolymphatic space was visually assessed relative to the enhancing perilymphatic space on delayed post-IT contrast FLAIR MRI sequences and characterized as <34%, 34-50% or >50% of endolymphatic/perilymphatic volume.
The relative volume of the scala media of the basal turn of the cochlea (non-enhancing endolymph) was visually assessed relative to the scala tympani and scala vestibuli (enhancing perilymph) on delayed post-IT contrast FLAIR MRI sequences. Cases were characterized as: No Cochlear EH (no perceptible distention of the scala media), Cochlear EH (perceptible distention of the scala media), or Absent enhancement (no contrast in the cochlear perilymph)
The fundus of the internal auditory canal (IAC) was visually inspected to determine if there was conspicuous, subtle, or no enhancement extending in the setting of prior IT contrast injection, indicating permeability of the cochlear modiolus.