This study aimed to assess the clinical implications of delayed-acquisition post-gadolinium magnetic resonance imaging in identifying endolymphatic hydrops in Ménière's disease.

This study was a systematic review using Medline and Embase and following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines with predetermined criteria, namely Ménière's disease, post-gadolinium magnetic resonance imaging and endolymphatic hydrops. The Quality Assessment of Diagnostic Accuracy Studies-2 tool was used to assess bias.

Eleven studies were included; they all used 3T magnetic resonance imaging, with three-dimensional fluid-attenuated inversion recovery being the most common sequence. Intravenous gadolinium administration was more widely used compared with the intratympanic route. As for the timing of acquisition, 4 hours post-administration was universally used for the IV gadolinium and 24 hours was used for the intratympanic gadolinium. Despite patient-selection associated bias, all studies reported adequate visualisation of the endolymphatic spaces.

The use of delayed-acquisition magnetic resonance imaging is increasingly supported in visualising the endolymphatic spaces in Ménière's disease. Although the accessibility of 3T magnetic resonance imaging questions its wider applicability, it is a promising tool for the near future.

To assess the feasibility of non-contrast T2-weighted magnetic resonance imaging as compared to T1-weighted post-contrast magnetic resonance imaging for detecting acoustic neuroma growth.

Adult patients with acoustic neuroma who underwent at least three magnetic resonance imaging scans of the internal auditory canals with and without contrast in the past nine years were identified. T1- and T2-weighted images were reviewed by three neuroradiologists, and tumour size was measured. Accuracy of the measurements on T2-weighted images was defined as a difference of less than or equal to 2 mm from the measurement on T1-weighted images.

A total of 107 magnetic resonance imaging scans of 26 patients were reviewed. Measurements on T2-weighted magnetic resonance imaging scans were 88 per cent accurate. Measurements on T2-weighted images differed from measurements on T1-weighted images by an average of 1.27 mm, or 10.4 per cent of the total size. The specificity of T2-weighted images was 88.2 per cent and the sensitivity was 77.8 per cent.

The T2-weighted sequences are fairly accurate in measuring acoustic neuroma size and identifying growth if one keeps in mind the caveats associated with the tumour characteristics or location.

To verify the hypothesis that intravenous frusemide reduces endolymphatic hydrops, as evaluated by three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging following intratympanic gadolinium administration.

The study comprised 12 patients (7 females and 5 males, aged 19–74 years) with Ménière's disease. Disease duration ranged from 0.5 to 8 years, with a frequency of 0.5 to 6 vertigo spells per month, as calculated in the last 6 months. Three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging was performed 24 hours after intratympanic injection of gadobutrol diluted eight-fold. Frusemide 20 mg was given intravenously immediately after imaging. Magnetic resonance imaging was repeated after 1 hour, using the same parameters and sequence.

All patients showed enhancement defects, indicating endolymphatic hydrops of variable degrees. No modifications occurred at the second magnetic resonance imaging performed 1 hour after frusemide administration.

There was no evidence of endolymphatic hydrops modification 1 hour after intravenously administered frusemide. Therefore, loop diuretics in Ménière's disease, which are today used on an empirical basis, must be reconsidered. Implications of these outcomes are discussed and related to the role of endolymphatic hydrops in the development of Ménière's disease.

Three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging of the inner ear after intratympanic injection of gadolinium, together with magnetic resonance imaging scoring of the perilymphatic space, were used to investigate the positive identification rate of hydrops and determine the technique's diagnostic value for delayed endolymphatic hydrops.

Twenty-five patients with delayed endolymphatic hydrops underwent pure tone audiometry, bithermal caloric testing, vestibular-evoked myogenic potential testing and three-dimensional magnetic resonance imaging of the inner ear after bilateral intratympanic injection of gadolinium. The perilymphatic space of the scanned images was analysed to investigate the positive identification rate of endolymphatic hydrops.

According to the magnetic resonance imaging scoring of the perilymphatic space and the diagnostic standard, 84 per cent of the patients examined had endolymphatic hydrops. In comparison, the positive identification rates for vestibular-evoked myogenic potential and bithermal caloric testing were 52 per cent and 72 per cent respectively.

Three-dimensional magnetic resonance imaging after intratympanic injection of gadolinium is valuable in the diagnosis of delayed endolymphatic hydrops and its classification. The perilymphatic space scoring system improved the diagnostic accuracy of magnetic resonance imaging.

To investigate the feasibility of postauricular hypodermic injection for treating inner ear disorders, we compared perilymph pharmacokinetics for postauricular versus intravenous injection, using magnetic resonance imaging, in an animal model.

Twelve albino guinea pigs were divided randomly into two groups and administered gadopentetate dimeglumine via either a postauricular or an intravenous bolus injection. A 7.0 Tesla magnetic resonance imaging system was used to assess the signal intensities of gadolinium-enhanced images of the cochlea, as a biomarker for changes in gadopentetate dimeglumine concentration in the perilymph. Pharmacokinetic parameters were calculated based on these signal intensity values.

Guinea pigs receiving postauricular injection showed longer times to peak signal intensity, longer elimination half-life, longer mean residence time and a greater area under the signal–time curve (from pre-injection to the last time point) (p < 0.05).

Postauricular injection shows potential as an efficient drug delivery route for the treatment of inner ear disorders.