Changes in endolymphatic hydrops in patients with Ménière's disease treated conservatively for more than 1 year

Regression of Endolymphatic Hydrops in Patient With Meniere's Disease Treated With Vestibular Neurectomy: A Case Report

Vestibular neurectomy is an effective method eliminating vertigo attacks in patients suffering from disabling Meniere's disease with no clinical improvement despite conservative and intratympanic therapy. Magnetic resonance imaging allows in vivo evaluation of changes manifesting in the inner ear after treatment; however, downgrading of the endolymphatic hydrops after vestibular neurectomy had not been previously described in the literature. In the present article, a case of a patient with unilateral severe Meniere's disease treated with selective vestibular nerve section from middle fossa approach was described. Clinical symptoms and audiovestibular tests were evaluated before and 13 months after the surgery. Complete resolution of vertigo episodes and hearing preservation was achieved. Magnetic resonance imaging was performed before and after the surgery using a 3 Tesla scanner with dedicated protocol after intravenous administration of gadolinium contrast agent. In the follow-up examination, regression of the cochlear and vestibular endolymphatic hydrops was visualized, which may suggest processes occurring in the labyrinth as a result of the vestibular efferent fibers section.

Improvement of vertigo symptoms and acoustic power absorbance in cases with endolymphatic hydrops

Objective

The pathophysiology and symptoms underlying Meniere's disease (MD) manifest as endolymphatic hydrops (EH), potentially impacting acoustic power absorbance in vestibular EH. The longitudinal effects of middle ear pressure therapy (MEPT) and conservative therapies for EH by magnetic resonance imaging (MRI) and on acoustic power absorbance on wideband acoustic immittance (WAI) were evaluated, and their changes were compared with clinical symptoms.

Methods

Eleven patients with definite MD or delayed endolymphatic hydrops (DEH), resistant to conservative therapies and who continued MEPT for 1 year, were included. Vertigo scores, hearing levels, acoustic power absorbance on WAI, and degrees of EH on 3-T MRI were evaluated and compared before and after the treatments.

Results

One year after the start of MEPT, all cases showed symptomatic improvement in vertigo score; however, the degrees of EH showed no improvements except in one case. In the affected ears with EH, their absorbances on WAI improved, particularly at 1580-1905 or 2400-2953 Hz (p < .05).

Conclusion

Alleviation of vestibular symptoms with the therapy of MD was not necessarily associated with improved EH. Vestibular symptoms could be related to the change in the impedance of inner ear pressure, which was proven by the normalization of acoustic power absorbance. Assessments of acoustic power absorbance may provide useful information for physiological conditions and causative factors of vertigo in ears with EH.

Level of evidence

4.

Temporal changes in endolymphatic hydrops on MRI with or without intervention: A systematic review

OBJECTIVE

The pathophysiology of Meniere's Disease (MD) involves endolymphatic hydrops (ELH) of the inner ear. Magnetic Resonance Imaging (MRI) has been shown to detect ELH, but changes in ELH have been poorly described using this modality. Our objective was to review MRI-measured changes in ELH over time and after medical and/or surgical intervention in patients with MD. We secondarily aim to associate changes in ELH with changes in MD symptomatology.

DATABASES REVIEWED

Medline, Web of Science, and Embase databases.

METHODS

A systematic review of articles was performed to identify studies utilizing MRI to measure ELH changes over time, and after medical or surgical treatment. Articles on non-human subjects and without direct measurement of ELH were excluded.

RESULTS

Of 532 studies identified, 12 were included, involving 170 patients (mean age 56.3 years). Ten studies were prospective; two were retrospective. Five studies strictly utilized medical means of intervention, four utilized surgical treatments, one utilized both, and two observed temporal changes without treatment. Across all interventions, 72.1 % of patients exhibited the same or worsening ELH on imaging. In studies reporting vertigo outcomes, 95.9 % of patients exhibited improvement after the treatment period.

CONCLUSION

Medical and surgical interventions often yield symptomatic relief of vertigo in MD patients despite stable or increasing ELH volume. MRI may have greater clinical utility in diagnosing ELH as opposed to assessing treatment response.

Changes in endolymphatic hydrops after vestibular neurectomy observed in magnetic resonance imaging - A pilot study

OBJECTIVES

The aim was to evaluate endolymphatic hydrops in patients with Ménière's disease before and after vestibular neurectomy to verify if the endolymphatic space dilatation, observed in magnetic resonance imaging, regressed within several months after surgery.

METHODS

Magnetic resonance imaging was performed after intravenous gadolinium injection in four patients with unilateral definite Ménière's disease before and eight months after vestibular neurectomy. Clinical symptoms, audiovestibular tests, and endolymphatic hydrops in magnetic resonance imaging were evaluated.

RESULTS

Endolymphatic hydrops was visualized in preoperative magnetic resonance imaging in three out of four analyzed patients. In the remaining one, an asymmetrical contrast enhancement in the affected ear was found. After the vestibular neurectomy, all four patients presented a complete resolution of vertigo episodes and improved functional level. Significant postoperative hearing deterioration was found in two patients. In the follow-up magnetic resonance imaging, no reduction of the endolymphatic hydrops was visualized. A reduction of asymmetrical contrast enhancement in one patient was found.

CONCLUSIONS

Magnetic resonance imaging of the inner ear is a helpful diagnostic tool for Menière's disease. Vestibular neurectomy is an effective treatment for intractable vertigo; however, there is no endolymphatic hydrops regression evidence within several months after the surgery. Therefore, further studies with a long follow-up period and repeated magnetic resonance imaging are needed to assess the vestibular neurectomy's impact on endolymphatic hydrops. Nevertheless, magnetic resonance imaging supports the clinical diagnosis of Ménière's disease and may help understand its pathophysiology.

Advanced Imaging of the Vestibular Endolymphatic Space in Ménière's Disease

The diagnosis of "definite" Méniére's disease (MD) relies upon its clinical manifestations. MD has been related with Endolymphatic Hydrops (EH), an enlargement of the endolymphatic spaces (ES) (cochlear duct, posterior labyrinth, or both). Recent advances in Magnetic Resonance (MR) imaging justify its increasing role in the diagnostic workup: EH can be consistently recognized in living human subjects by means of 3-dimensional Fluid-Attenuated Inversion-Recovery sequences (3D-FLAIR) acquired 4 h post-injection of intra-venous (i.v.) Gadolinium-based contrast medium, or 24 h after an intratympanic (i.t.) injection. Different criteria to assess EH include: the comparison of the area of the vestibular ES with the whole vestibule on an axial section; the saccule-to-utricle ratio ("SURI"); and the bulging of the vestibular organs toward the inferior 1/3 of the vestibule, in contact with the stapedial platina ("VESCO"). An absolute link between MD and EH has been questioned, since not all patients with hydrops manifest MD symptoms. In this literature review, we report the technical refinements of the imaging methods proposed with either i.t. or i.v. delivery routes, and we browse the outcomes of MR imaging of the ES in both MD and non-MD patients. Finally, we summarize the following imaging findings observed by different researchers: blood-labyrinthine-barrier (BLB) breakdown, the extent and grading of EH, its correlation with clinical symptoms, otoneurological tests, and stage and progression of the disease.

Intravenous Delayed Gadolinium-Enhanced MR Imaging of the Endolymphatic Space: A Methodological Comparative Study

In-vivo non-invasive verification of endolymphatic hydrops (ELH) by means of intravenous delayed gadolinium (Gd) enhanced magnetic resonance imaging of the inner ear (iMRI) is rapidly developing into a standard clinical tool to investigate peripheral vestibulo-cochlear syndromes. In this context, methodological comparative studies providing standardization and comparability between labs seem even more important, but so far very few are available. One hundred eight participants [75 patients with Meniere's disease (MD; 55.2 ± 14.9 years) and 33 vestibular healthy controls (HC; 46.4 ± 15.6 years)] were examined. The aim was to understand (i) how variations in acquisition protocols influence endolymphatic space (ELS) MR-signals; (ii) how ELS quantification methods correlate to each other or clinical data; and finally, (iii) how ELS extent influences MR-signals. Diagnostics included neuro-otological assessment, video-oculography during caloric stimulation, head-impulse test, audiometry, and iMRI. Data analysis provided semi-quantitative (SQ) visual grading and automatic algorithmic quantitative segmentation of ELS area [2D, mm²] and volume [3D, mm³] using deep learning-based segmentation and volumetric local thresholding. Within the range of 0.1-0.2 mmol/kg Gd dosage and a 4 h ± 30 min time delay, SQ grading and 2D- or 3D-quantifications were independent of signal intensity (SI) and signal-to-noise ratio (SNR; FWE corrected, p < 0.05). The ELS quantification methods used were highly reproducible across raters or thresholds and correlated strongly (0.3-0.8). However, 3D-quantifications showed the least variability. Asymmetry indices and normalized ELH proved the most useful for predicting quantitative clinical data. ELH size influenced SI (cochlear basal turn p < 0.001), but not SNR. SI could not predict the presence of ELH. In conclusion, (1) Gd dosage of 0.1-0.2 mmol/kg after 4 h ± 30 min time delay suffices for ELS quantification. (2) A consensus is needed on a clinical SQ grading classification including a standardized level of evaluation reconstructed to anatomical fixpoints. (3) 3D-quantification methods of the ELS are best suited for correlations with clinical variables and should include both ears and ELS values reported relative or normalized to size. (4) The presence of ELH increases signal intensity in the basal cochlear turn weakly, but cannot predict the presence of ELH.

Magnetic resonance imaging of the inner ear in the diagnostics of Ménière's disease

Ménière's disease is characterized by sudden episodes of vertigo accompanied by tinnitus and/or feeling of fullness in the ear as well as fluctuating sensorineural hearing loss. Despite numerous studies, the etiology of this disease remains unknown. However, the enlargement of the inner ear's endolymphatic spaces, referred to as endolymphatic hydrops, is considered the underlying condition. Thanks to recent advances in magnetic resonance (MR) technology, it is now possible to obtain in vivo imaging of endolymphatic hydrops in patients presenting with Ménière's disease symptoms. Visualization of the inner ear fluid compartments is achieved after gadolinium contrast is administered into the tympanic cavity or via the intravenous route. Evaluation of endolymphatic hydrops is possible as the contrast agent selectively penetrates the perilymph, and endolymph is visualized as contrast defects. The currently used radiological hydrops grading systems include qualitative, semi-quantitative, and volumetric scales. The methods are subject to ongoing modifications to increase their sensitivity and specificity. Numerous studies describe correlations between clinical symptoms and audiological and otoneurological examination results with the endolymphatic hydrops grade. MRI is also applicable in patients' diagnostics with an incomplete or atypical course of the Ménière's disease. In the course of the treatment, follow-up MRI scans enable assessing individual treatment modalities' efficacy in terms of the severity of lesions and the further course of the disease within the inner ear.

Effects of endolymphatic hydrops on acoustic energy absorbance

Background: The presence of endolymphatic hydrops (EH) may cause hearing loss and affect the transmission of acoustic energy to the inner ear.Objectives: Acoustic energy absorbance on wideband acoustic immittance (WAI) was evaluated, focusing especially on EH in the vestibule.Material and methods: A total of 32 ears from 16 patients who underwent 3-T magnetic resonance imaging (MRI) to evaluate the presence of EH were examined, retrospectively. The degree of EH in the vestibule was classified into three grades (no, mild, and significant), and pure tone audiometry (PTA) and WAI were measured before and after a glycerol drip.Results: Ears with significant EH showed significantly higher hearing levels and air-bone gaps (ABG), and higher absorbance values on WAI at low frequencies (560-600 Hz) than ears with mild or no EH. Changes in absorbance values were observed in some ears without threshold change on PTA.Conclusions and Significance: This study showed significantly higher absorbance values of acoustic energy with significant vestibular EH at low frequencies. Considering ABGs observed in ears with significant EH, the presence of EH in the vestibule might cause an obstacle to the transmission of acoustic energy to the inner ear.

Clinical Practice Guideline: Ménière's Disease

OBJECTIVE

Ménière's disease (MD) is a clinical condition defined by spontaneous vertigo attacks (each lasting 20 minutes to 12 hours) with documented low- to midfrequency sensorineural hearing loss in the affected ear before, during, or after one of the episodes of vertigo. It also presents with fluctuating aural symptoms (hearing loss, tinnitus, or ear fullness) in the affected ear. The underlying etiology of MD is not completely clear, yet it has been associated with inner ear fluid (endolymph) volume increases, culminating in episodic ear symptoms (vertigo, fluctuating hearing loss, tinnitus, and aural fullness). Physical examination findings are often unremarkable, and audiometric testing may or may not show low- to midfrequency sensorineural hearing loss. Conventional imaging, if performed, is also typically normal. The goals of MD treatment are to prevent or reduce vertigo severity and frequency; relieve or prevent hearing loss, tinnitus, and aural fullness; and improve quality of life. Treatment approaches to MD are many and typically include modifications of lifestyle factors (eg, diet) and medical, surgical, or a combination of therapies.

PURPOSE

The primary purpose of this clinical practice guideline is to improve the quality of the diagnostic workup and treatment outcomes of MD. To achieve this purpose, the goals of this guideline are to use the best available published scientific and/or clinical evidence to enhance diagnostic accuracy and appropriate therapeutic interventions (medical and surgical) while reducing unindicated diagnostic testing and/or imaging.

Tinnitus in the side with better hearing

OBJECTIVES

We aimed to confirm the characteristics of patients with tinnitus in the better-hearing side.

MATERIALS AND METHODS

Among the 778 patients who visited the tinnitus clinic complaining of unilateral tinnitus at a local university hospital between March 2014 and December 2017, we recruited 62 patients who showed tinnitus in the better-hearing side on pure-tone audiometry. The mean hearing threshold was calculated using the arithmetic mean of the pure tone thresholds at 1, 2, 3, and 4 kHz. In addition, patients' medical history, tinnitus questionnaires, and other audiologic test results were thoroughly analyzed together for diagnosis.

RESULTS

Fluctuating hearing loss without vertigo or Ménière's disease were the most common etiologies (n = 16, 25.8%), followed by high-frequency hearing loss (n = 13, 21.0%), sudden idiopathic hearing loss (n = 6, 9.7%), and presbycusis (n = 6, 9.7%). Somatosensory tinnitus was also observed in seven patients. Neck pain was associated with tinnitus in five patients (8.1%), and two other patients (3.2%) experienced temporomandibular disorder in the same side as the tinnitus.

CONCLUSION

Tinnitus was associated with deterioration of hearing even when it occurred in the better-hearing side. Among the possible etiologies, fluctuating hearing loss in the tinnitus side was the most common audiologic finding. Assessment of hearing level at each frequency was more effective in detecting high-frequency hearing loss rather than the use of the mean hearing level. In addition, somatosensory tinnitus should not be ignored.

MR imaging of endolymphatic hydrops in Ménière's disease: not all that glitters is gold

Ménière's disease (MD) is a chronic condition characterised by fluctuating hearing loss, intermittent vertigo, tinnitus and aural fullness. Its anatomical and pathological counterpart is represented by endolymphatic hydrops (EH). Recent development and progress in magnetic resonance (MR) imaging techniques has enabled visualisation of EH in living human subjects using a 3 Tesla (T) scanner and gadolinium-based contrast-agent (GBCA) via intravenous (IV) or intra-tympanic (IT) administration. Data emerging from the literature about MR imaging of EH in MD patients are limited, and we therefore reviewed the most common MR imaging findings in the study of the endolymphatic space in both MD and non-MD patients.

Meniere's disease

Meniere's disease (MD) is a disorder of the inner ear that causes vertigo attacks, fluctuating hearing loss, tinnitus and aural fullness. The aetiology of MD is multifactorial. A characteristic sign of MD is endolymphatic hydrops (EH), a disorder in which excessive endolymph accumulates in the inner ear and causes damage to the ganglion cells. In most patients, the clinical symptoms of MD present after considerable accumulation of endolymph has occurred. However, some patients develop symptoms in the early stages of EH. The reason for the variability in the symptomatology is unknown and the relationship between EH and the clinical symptoms of MD requires further study. The diagnosis of MD is based on clinical symptoms but can be complemented with functional inner ear tests, including audiometry, vestibular-evoked myogenic potential testing, caloric testing, electrocochleography or head impulse tests. MRI has been optimized to directly visualize EH in the cochlea, vestibule and semicircular canals, and its use is shifting from the research setting to the clinic. The management of MD is mainly aimed at the relief of acute attacks of vertigo and the prevention of recurrent attacks. Therapeutic options are based on empirical evidence and include the management of risk factors and a conservative approach as the first line of treatment. When medical treatment is unable to suppress vertigo attacks, intratympanic gentamicin therapy or endolymphatic sac decompression surgery is usually considered. This Primer covers the pathophysiology, symptomatology, diagnosis, management, quality of life and prevention of MD.

Simple Estimation of the Endolymphatic Volume Ratio after Intravenous Administration of a Single-dose of Gadolinium Contrast

PURPOSE

To evaluate the feasibility of a simple estimation for the endolymphatic volume ratio (endolymph volume/total lymph volume = %EL_volume) from an area ratio obtained from only one slice (%EL_1slice) or from three slices (%EL_3slices). The %EL_volume, calculated from a time-consuming measurement on all magnetic resonance (MR) slices, was compared to the %EL_1slice and the %EL_3slices.

METHODS

In 40 ears of 20 patients with a clinical suspicion of endolymphatic hydrops, MR imaging was performed 4 hours after intravenous administration of a single dose of gadolinium-based contrast material (IV-SD-GBCM). Using previously reported HYDROPS2-Mi2 MR imaging, the %EL_volume values in the cochlea and the vestibule were measured separately by two observers. The correlations between the %EL_1slice or the %EL_3slices and the %EL_volume values were evaluated.

RESULTS

A strong linear correlation was observed between the %EL_volume and the %EL_3slices or the %EL_1slice in the cochlea. The Pearson correlation coefficient (r) was 0.968 (3 slices) and 0.965 (1 slice) for observer A, and 0.968 (3 slices) and 0.964 (1 slice) for observer B (P < 0.001, for all). A strong linear correlation was also observed between the %EL_volume and the %EL_3slices or the %EL_1slice in the vestibule. The Pearson correlation coefficient (r) was 0.980 (3 slices) and 0.953 (1 slice) for observer A, and 0.979 (3 slices) and 0.952 (1 slice) for observer B (P < 0.001, for all). The high intra-class correlation coefficients (0.991-0.997) between the endolymph volume ratios by two observers were observed in both the cochlea and the vestibule for values of the %EL_volume, the %EL_3slices and the %EL_1slice.

CONCLUSION

The %EL_volume might be easily estimated from the %EL_3slices or the %EL_1slice.