| Summary: | Ménière’s disease (MD) is a debilitating condition typically presenting with slow-developing unilateral symptoms of hearing loss, vertigo, tinnitus and aural fullness.
The disease progresses to the contralateral ear in up to 50% of cases. Currently, there is a significant delay between symptom onset and diagnosis, and therefore effective
treatment. Contrast-enhanced Magnetic Resonance Imaging (MRI) for diagnosing MD is currently used in research settings to detect endolymphatic hydrops (EH), which
can be present in unaffected ears and other audio-vestibular conditions but is universally recognised as a biological marker consistent with the diagnosis of MD.
MRI could expedite diagnosis and guide management as it could detect EH in the unaffected, clinically ‘silent’, ear which would develop symptoms later, detracting from ablative treatments which control symptoms by destroying the function of the ear rendering the patient with severe bilateral hypovestibular function. MRI is currently not used for diagnosis of MD outside of research settings in the UK and
there is no globally accepted scanning protocol adopted in wider clinical practice as image quality and interpretation depend on the different settings and image parameters enabled in different makes of MR scanners, different image acquisition parameters and observer expertise. MRI is not yet a part of the NICE diagnostic pathway for MD.
This motivated an exploratory study at the Sir Peter Mansfield Imaging Centre, University of Nottingham to develop an MR scanning protocol for MD patients. The
overall aim was to optimise an MR image acquisition protocol for EH detection in MD which would be translatable into clinical practice. This was supported by a comprehensive scoping review synthesising the evidence behind the use of MRI in EH detection and MD diagnosis. First, MR images of 4 healthy participants for anatomical reference and experience of image interpretation were obtained; then images of 4
MD patients were obtained both with and without contrast enhancement and 4 hours post-IV contrast administration using a 3D Fluid Attenuation Inversion Recovery
sequence on a 3 T MR scanner. One MD patient was also scanned with a 3D Real Inversion recovery sequence and 2 hours post-contrast for a single-case comparison.
The following scanning parameters were adjusted throughout the study for optimisation of the scanning protocol on a case-by-case basis; repetition time, inversion time and slice thickness which also influenced scanning time.
All images were qualitatively and semiquantitatively analysed by a single, unblinded observer. Image quality was measured by contrast to noise ratio and EH was detected
and graded as per established criteria. All MD patients had EH in the affected ears, and 3 MD patients (75%) had EH in the unaffected ear consistently throughout contrast-enhanced scans. All healthy participants showed EH on at least one of the scanning protocols likely due to the quality of images produced by a specific acquisition sequence. Non-contrast enhanced images were inconclusive. The study was limited by a small sample size and a lack of interobserver agreement.
However, the scanning protocol using a 3D Fluid Attenuation Recovery with a repetition time of 12000 ms, slice thickness of 0.7 mm and inversion time of 2500 ms was deemed optimal given the consistency of image quality and accuracy of EH
detection. This constitutes an applicable scanning protocol which was developed and can be implemented into local clinical practice in Nottingham.
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