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

Stratification of patients with Menière's disease based on eye movement videos recorded from the beginning of vertigo attacks and contrast-enhanced MRI findings

Purpose

Diagnosis of Menière's disease (MD) relies on subjective factors and the patients diagnosed with MD may have heterogeneous pathophysiologies. This study aims to stratify MD patients using two objective data, nystagmus videos and contrast-enhanced magnetic resonance imaging (CE-MRI).

Methods

This is a retrospective cross-sectional study. According to the Japan Society for Equilibrium Research criteria (c-JSER), adults diagnosed with definite MD and who obtained videos recorded by portable nystagmus recorder immediately following vertigo attacks and underwent CE-MRI of the inner ear were included (ss = 91). Patients who obtained no nystagmus videos, who had undergone sac surgery, and those with long examination intervals were excluded (n = 40).

Results

The gender of the subjects was 22 males and 29 females. The age range was 20-82 y, with a median of 54 y. Endolymphatic hydrops (EH) were observed on CE-MRI in 84% (43 patients). Thirty-one patients had unilateral EH. All of them demonstrated EH on the side of the presence of cochlear symptoms. The number of patients who had both nystagmus and EH was 38. Five patients only showed EH and 5 patients only exhibited nystagmus, while 3 patients did not have either. Of the 43 nystagmus records, 32 showed irritative nystagmus immediately after the vertigo episode. The direction of nystagmus later reversed in 44% of cases over 24 h.

Conclusion

Patients were stratified into subgroups based on the presence or absence of EH and nystagmus. The side with cochlear symptoms was consistent with EH. The c-JSER allows for the diagnosis of early-stage MD patients, and it can be used to treat early MD and preserve hearing; however, this approach may also include patients with different pathologies.

Delayed post gadolinium MRI descriptors for Meniere's disease: a systematic review and meta-analysis

OBJECTIVES

Delayed post-gadolinium magnetic resonance imaging (MRI) detects changes of endolymphatic hydrops (EH) within the inner ear in Meniere's disease (MD). A systematic review with meta-analysis was conducted to summarise the diagnostic performance of MRI descriptors across the range of MD clinical classifications.

MATERIALS AND METHODS

Case-controlled studies documenting the diagnostic performance of MRI descriptors in distinguishing MD ears from asymptomatic ears or ears with other audio-vestibular conditions were identified (MEDLINE, EMBASE, Web of Science, Scopus databases: updated 17/2/2022). Methodological quality was evaluated with Quality Assessment of Diagnostic Accuracy Studies version 2. Results were pooled using a bivariate random-effects model for evaluation of sensitivity, specificity and diagnostic odds ratio (DOR). Meta-regression evaluated sources of heterogeneity, and subgroup analysis for individual clinical classifications was performed.

RESULTS

The meta-analysis included 66 unique studies and 3073 ears with MD (mean age 40.2-67.2 years), evaluating 11 MRI descriptors. The combination of increased perilymphatic enhancement (PLE) and EH (3 studies, 122 MD ears) achieved the highest sensitivity (87% (95% CI: 79.92%)) whilst maintaining high specificity (91% (95% CI: 85.95%)). The diagnostic performance of "high grade cochlear EH" and "any EH" descriptors did not significantly differ between monosymptomatic cochlear MD and the latest reference standard for definite MD (p = 0.3; p = 0.09). Potential sources of bias were case-controlled design, unblinded observers and variable reference standard, whilst differing MRI techniques introduced heterogeneity.

CONCLUSIONS

The combination of increased PLE and EH optimised sensitivity and specificity for MD, whilst some MRI descriptors also performed well in diagnosing monosymptomatic cochlear MD.

KEY POINTS

• A meta-analysis of delayed post-gadolinium magnetic resonance imaging (MRI) for the diagnosis of Meniere's disease is reported for the first time and comprised 66 studies (3073 ears). • Increased enhancement of the perilymphatic space of the inner ear is shown to be a key MRI feature for the diagnosis of Meniere's disease. • MRI diagnosis of Meniere's disease can be usefully applied across a range of clinical classifications including patients with cochlear symptoms alone.

A systematic review on delayed acquisition of post-gadolinium magnetic resonance imaging in Ménière's disease: imaging of the endolymphatic spaces

OBJECTIVE

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

METHOD

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.

RESULTS

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.

CONCLUSION

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.

Characteristics of clinical details and endolymphatic hydrops in unilateral and bilateral Ménière's disease in a single Asian group

Objectives

To elucidate the characteristics of the clinical details and endolymphatic hydrops (EH) in bilateral Ménière's disease (BMD).

Methods

A total of 545 patients with definite MD were enrolled. Demographic variables; the age of onset; disease course; inner ear function; the coexistence of related disorders such as migraine, delayed MD, drop attacks, and autoimmune diseases; familial history; and characteristics of EH were analyzed.

Results

In the study population, the prevalence of BMD was 15.4%. The disease duration of BMD (84.0 ± 89.6 months) was significantly longer than that of unilateral MD (UMD, 60.1 ± 94.0 months) (P = 0.001). As evaluated by hearing thresholds and cervical and ocular vestibular evoked myogenic potentials, inner ear functions were more deteriorated in BMD (P < 0.05) than in UMD. The proportions of delayed MD and a family history of vertigo were significantly larger in BMD (P < 0.05). EH was observed in 100% of cases on the clinically affected side and 6.1% of cases on the unaffected side.

Conclusion

A low prevalence of BMD, longer disease duration, higher frequencies of delayed MD, and family history of vertigo in patients with BMD were significant findings observed in the present study. All affected ears presented with EH, and a low percentage of unaffected sides presented with EH.

Auditory Manifestations of Vestibular Migraine

Objectives

To investigate the auditory features of patients with vestibular migraine (VM) and to analyze the possible relevant factors of hearing loss.

Methods

A total of 166 patients with VM were enrolled. Demographic variables, age of onset, disease course, distribution of vestibular attacks, characteristics of hearing loss, and the coexistence of related disorders, such as visual aura, familial history, motion sickness, nausea, headache, photophobia, otalgia, tinnitus, aural fullness, and phonophobia, were analyzed and compared.

Results

Patients with VM can manifest otalgia (8.4%), tinnitus (51.8%), aural fullness (41%), and phonophobia (31.9%). Of 166 patients, the prevalence of VMw was 21.1% (n = 35). Patients with VMw mainly manifested mild and easily reversible low-frequency hearing loss. The proportions of tinnitus and aural fullness were significantly larger in patients with VMw than that in patients with VMo (P < 0.05). The duration of vestibular symptoms was significantly shorter in patients with VMw (P < 0.05). However, the age of onset, disease course, gender, frequency of vestibular attacks, the coexistence of visual aura, familial history, motion sickness, nausea, headache, photophobia, otalgia, and phonophobia had no significant difference between the two groups.

Conclusion

Auditory symptoms were common in patients with VM. The hearing loss of VM was characterized by a mild and easily reversible low-frequency hearing loss, accompanied by higher proportions of tinnitus and aural fullness, and a shorter duration of vestibular symptoms compared with patients with VMo.

Low Frequency Air-Bone Gap in Meniere's Disease: Relationship With Magnetic Resonance Imaging Features of Endolymphatic Hydrops

OBJECTIVES

The appearance of low-frequency air-bone gaps (LFABGs) in Meniere's disease (MD) is a recognized but relatively unexplored phenomenon. Two theories have been proposed to explain their etiology: increased perilymphatic pressure resulting in either reduced stapedial mobility or dampened transmission of acoustic energy, and direct contact between the dilated saccule and the stapes footplate. The aim of this study was to evaluate these two hypotheses by comparing delayed postgadolinium magnetic resonance imaging (MRI) features of two groups of patients with unilateral definite MD, those with and without LFABGs.

DESIGN

This retrospective case-control study was conducted at a tertiary otolaryngology unit in the United Kingdom. The study included 35 patients who satisfied the 2015 Barany criteria for unilateral definite MD. The cohort was divided into two groups, those with LFABGs (LFABG+ group) and those without (LFABG- group), according to the pure-tone audiometry performed within 6 months of MRI. Alternative potential causes for the LFABGs were excluded on the basis of otologic history, otoscopy, tympanometry, and/or imaging. Using a 4-hr delayed postgadolinium 3-dimensional fluid-attenuated inversion recovery sequence, two observers evaluated the severity of cochlear and vestibular endolymphatic hydrops (EH) and the presence of vestibular endolymphatic space contacting the oval window (VESCO). The air and bone conduction thresholds, ABGs and MRI features were compared between the LFABG+ and LFABG- groups. Where any of the variables were found to be significantly associated with the presence of ABGs, further analysis was performed to determine whether or not they were independent predictors. Continuous variables were compared using the independent t test if normally distributed, and the Mann-Whitney U test or Kruskall-Wallis test if not normally distributed. Categorical variables were compared with Pearson's Chi-squared test or Fishers/Fisher-Freeman-Halton exact tests.

RESULTS

There were 10 patients in the LFABG+ group (28.6%) and 25 patients in the LFABG- group (71.4%). The mean ABGs in the symptomatic ear at 500 Hz, 1 kHz, and 2 kHz were 15.1 dB ± 6.4, 10.5 dB ± 9.0, and 4.0 dB ± 7.7, respectively, in the LFABG+ group and 2.0 ± 5.8, 2.4 ± 4.4, and -0.8 ± 4.7 dB in the LFABG- group. The differences in ABGs between the two groups were statistically significant at all three test frequencies ( p < 0.001 at 500 Hz, p = 0.007 at 1 kHz, and p = 0.041 at 2 kHz). The presence of ABGs was significantly associated with both the grade of vestibular EH ( p = 0.049) and VESCO ( p = 0.009). Further analysis showed a statistically significant association between the grade of vestibular EH and VESCO ( p = 0.007), and only VESCO was an independent variable associated with the presence of LFABGs ( p = 0.045).

CONCLUSIONS

The study findings add to the existing body of evidence that LFABGs are a true audiological finding in MD and allow us to propose a mechanism. Analysis of delayed gadolinium-enhanced MRI suggests that direct contact between the distended saccule and the inner surface of the stapes footplate is the more likely underlying pathophysiological mechanism for this audiometric phenomenon.

Consensus on MR Imaging of Endolymphatic Hydrops in Patients With Suspected Hydropic Ear Disease (Meniere)

Endolymphatic hydrops (EH) is considered the histological hallmark of Meniere's disease. Visualization of EH has been achieved by special sequences of inner ear magnetic resonance imaging (MRI) with a gadolinium-based contrast agent via intravenous or intratympanic administration. Although it has been applied for more than 10 years since 2007, a unified view on this technique has not yet been achieved. This paper presents an expert consensus on MRI of endolymphatic hydrops in the following aspects: indications and contra-indications for patient selection, methods of contrast-agent administration (intravenous or intratympanic), MRI sequence selection, the specific scanning parameter settings, and standard image evaluation methods and their advantages and disadvantages. For each part of this consensus, a comment is attached to elucidate the reasons for the recommendation.

Autoimmune Vestibulopathy—A Case Series

Autoimmune inner ear disease (AIED) is a rare clinical entity. Its pathogenicity, heterogenous clinical presentation in the context of secondary systemic autoimmune disease and optimal treatment avenues remain poorly understood. Vestibular impairment occurring in the context of AIED is rarely subject to detailed investigation given that the auditory symptoms and their responsiveness to immunosuppression are the focus of the few proposed diagnostic criteria for AIED. We present three cases of vestibulopathy occurring in the context of autoimmune inner ear conditions, including the first known report of autoimmune inner ear pathology arising with a temporal association to administration of the Pfizer-BioNTech SARS-CoV2 vaccination. We review the available literature pertinent to each case and summarise the key learning points, highlighting the variable presentation of vestibular impairment in AIED.

A finite element model to predict the consequences of endolymphatic hydrops in the basilar membrane

Ménière's disease is an inner ear disorder, associated with episodes of vertigo, fluctuant hearing loss, tinnitus, and aural fullness. Ménière's disease is associated with endolymphatic hydrops. Clinical evidences show that this disease is often incapacitating, negatively affecting the patients' everyday life. The pathogenesis of Ménière's disease is still not fully understood and remains unclear. Previous numerical studies available in the literature related with endolymphatic hydrops, are very scarce. The present work applies the finite element method to investigate the consequences of endolymphatic hydrops in the normal hearing, associated with the Ménière's disease. The obtained results for the steady state dynamics analysis are in accordance with clinical evidences. The results show that the basilar membrane is not affected in the same intensity along its length and that the lower frequencies are more affected by the endolymphatic hydrops. From a clinical point of view, this work shows the relationship between the increasing of the endolymphatic pressure and the development of hearing loss.

Intraoperative Electrocochleography in Subjects Affected by Vestibular Schwannoma and Ménière's Disease: Comparison of Results

OBJECTIVES

Histologic reports of temporal bones of ears with vestibular schwannomas (VSs) have indicated findings of endolymphatic hydrops (ELH) in some cases. The main goal of this investigation was to test ears with VSs to determine if they exhibit electrophysiological characteristics similar to those of ears expected to experience ELH.

DESIGN

Fifty-three subjects with surgically confirmed VS aged ≥18 and with normal middle ear status were included in this study. In addition, a second group of adult subjects (n = 24) undergoing labyrinthectomy (n = 6) or endolymphatic sac decompression and shunt (ELS) placement (n = 18) for poorly controlled vestibular symptoms associated with Meniere's disease (MD) participated in this research. Intraoperative electrocochleography (ECochG) from the round window was performed using tone burst stimuli. Audiometric testing and word recognition scores (WRS) were performed preoperatively. ECochG amplitudes, cochlear microphonic/auditory nerve neurophonic (ANN) in the form of the "ongoing" response and summation potential, were analyzed and compared between the two groups of subjects. In addition, to evaluate any effect of auditory nerve function, the auditory nerve score was calculated for each subject. Pure-tone averages were obtained using the average air conduction thresholds at 0.5, 1, and 2 kHz while WRS was assessed using Northwestern University Auditory Test No. 6 word lists.

RESULTS

In the VS group the average pure-tone averages and WRS were 59.6 dB HL and 44.8%, respectively, while in the MD group they were 52.3 dB HL and 73.8%. ECochG findings in both groups revealed a reduced trend in amplitude of the ongoing response with increased stimulus frequency. The summation potential amplitudes of subjects with VS were found to be less negative than the MD subjects for nearly all test frequencies. Finally, the VS group exhibited poorer amounts of auditory nerve function compared to the MD group.

CONCLUSIONS

The current findings suggest cochlear pathology (e.g., hair cell loss) in both groups but do not support the hypothesis that VSs cause ELH.

Neuroimaging of Dizziness and Vertigo

Dizziness and vertigo are common symptoms in the primary care and emergency settings, resulting in a significant decrease in quality of life and a high cost burden to the US health care system. The etiology of these symptoms is difficult to elucidate owing to a wide range of diseases with overlapping manifestations. The broad differential diagnosis based on whether the disease process is central or peripheral is showcased. Each differential will be categorized into neoplastic, infectious or inflammatory, structural, traumatic, and iatrogenic causes. Computed tomography scans, MRI, and vascular imaging are frequently complimentary in providing diagnoses and guidance in management.

High-quality imaging of endolymphatic hydrops acquired in 7 minutes using sensitive hT2W-3D-FLAIR reconstructed with magnitude and zero-filled interpolation

Background

It is still challenging to detect endolymphatic hydrops (EH) in patients with Meniere’s disease (MD) using MRI. The aim of the present study was to optimize a sensitive technique generating strong contrast enhancement from minimum gadolinium–diethylenetriamine pentaacetic acid (Gd–DTPA) while reliably detecting EH in the inner ear, including the apex.

Materials and methods

All imaging was performed using a 3.0 T MR system 24 h after intratympanic injection of low-dose Gd–DTPA. Heavily T2-weighted 3-dimensional fluid-attenuated inversion recovery reconstructed with magnitude and zero-filled interpolation (hT₂W–FLAIR–ZFI) was optimized and validated in phantom studies and compared with medium inversion time inversion recovery imaging with magnitude reconstruction (MIIRMR). The following parameters were used in hT₂W–FLAIR–ZFI: repetition time 14,000 ms, echo time 663 ms, inversion time 2900 ms, flip angle 120°, echo train length 271, and field of view 166 × 196 mm².

Results

MRI obtained using hT₂W–FLAIR–MZFI yielded high-quality images with sharper and smoother borders between the endolymph and perilymph and a higher signal intensity ratio and more homogenous perilymph enhancement than those generated with MIIRMR (p < 0.01). There were predominantly grade II EHs in the cochleae and grade III EHs in the vestibule in definite MD. EH was detected in the apex of 11/16 ipsilateral ears, 3/16 contralateral ears in unilateral definite MD and 3/6 ears in bilateral MD.

Conclusions

The novel hT₂W–FLAIR–MZFI technique is sensitive and demonstrates strong and homogenous enhancement by minimum Gd–DTPA in the inner ear, including the apex, and yields high-quality images with sharp borders between the endolymph and perilymph.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00405-021-06912-4.

MRI With Intratympanic Gadolinium: Comparison Between Otoneurological and Radiological Investigation in Menière's Disease

Objectives/hypothesis: To compare findings obtained using both magnetic resonance imaging plus intratympanic gadolinium and audiovestibular testing for Menière's disease.

Study design: Retrospective cohort study.

Methods: Patients with definite unilateral Menière's disease (n = 35) diagnosed according to 2015 Barany Criteria were included. Three-dimensional real inversion recovery (3D-real-IR) MRI was executed 24 h after intratympanic gadolinium injection to assess the presence and degree of endolymphatic hydrops. Pure tone audiometry, bithermal caloric test, head impulse test, ocular, and cervical VEMPs using air-conducted sound were performed to evaluate the level of hearing and vestibular loss. The results were compared to verify precision of the method in providing correct diagnoses.

Results: Different degrees of endolymphatic hydrops were observed in the MRI of the cochlea and vestibule in the affected ears of Menière's disease patients, even though it was impossible to radiologically distinguish the two otolithic structures separately. The correlation between the degree of linked alterations between instrumental and MRI testing was statistically significant. In particular, an 83% correspondence with audiometry, a 63% correspondence for cVEMPs and 60% correspondence for cVEMPs were seen. While for HIT the accordance was 70 and 80% for caloric bithermal test.

Conclusions: MRI using intratympanic gadolinium as a contrast medium has proved to be a reliable and harmless method, even though there is an objective difficulty in disclosing macular structures. The study revealed that there is no complete agreement between instrumental values and MRI due to the definition of the image and fluctuation of symptoms. The present work highlights the greater (but not absolute) sensitivity of otoneurological tests while MRI, although not yet essential for diagnosis, is certainly important for understanding the disease and its pathogenic mechanisms.

Assessment of the Membranous Labyrinth in Infants Using a Heavily T2-weighted 3D FLAIR Sequence without Contrast Agent Administration

BACKGROUND AND PURPOSE

Imaging is fundamental to assessing the acoustic pathway in infants with congenital deafness. We describe our depiction of the membranous labyrinth in infants using the heavily T2-weighted 3D FLAIR sequence without a contrast agent.

MATERIALS AND METHODS

We retrospectively reviewed 10 infants (20 ears) (median term equivalent age: 2 weeks; IQR: 1-5 weeks) who had undergone brain MR imaging including a noncontrast heavily T2-weighted 3D FLAIR scan of the temporal bone. For each ear, 3 observers analyzed, in consensus, the saccule, the utricle, and the 3 ampullae, assessing the visibility (score 0, not appreciable; score 1, visible without well-defined boundaries; score 2, visible with well-defined boundaries) and morphology ("expected" or "unexpected" compared with adults). The heavily T2-weighted 3D FLAIR sequence was scored for overall quality (score 0, inadequate; score 1, adequate but with the presence of image degradation; score 2, adequate).

RESULTS

Six (60%) MR examinations were considered adequate (score 1 or 2). The saccule was visible in 10 ears (83.3%) with an expected morphology in 9 ears (90%). In 1 ear of an infant with congenital deafness, the saccule showed an unexpected morphology. The utricle was visible as expected in 12 ears (100%). The lateral ampulla was visible in 5 ears (41.6%), the superior ampulla was visible in 6 ears (50.0%), and the posterior ampulla was visible in 6 ears (50.0%), always with expected morphology (100%).

CONCLUSIONS

MR imaging can depict the membranous labyrinth in infants using heavily T2-weighted 3D FLAIR without an injected contrast agent, but the sequence acquisition time reduces its feasibility in infants undergoing MR studies during natural sleep.

Which is the optimally defined vestibular cross-section to diagnose unilateral Meniere's disease with delayed post-gadolinium 3D fluid-attenuated inversion recovery MRI?

OBJECTIVES

Delayed post-gadolinium 3D fluid-attenuated inversion recovery (FLAIR) MRI is used to support a diagnosis of Ménière's disease (MD) with the ratio of the endolymphatic space (ES) to the sum of the endolymphatic and perilymphatic spaces (SEPS) on a cross-section through the vestibule being a key diagnostic criterion. It was hypothesised that the exact definition of the vestibular cross-section would influence the ES: SEPS ratio, its ability to diagnose MD, and its reproducibility.

METHODS

Following institutional approval, 22 patients (five male, 17 female; mean age 52.1) with unilateral MD and delayed post-gadolinium 3D FLAIR MRI were retrospectively analysed. Two observers measured the ES and SEPS on predefined axial (superior and inferior) and sagittal vestibular cross-sections. Receiver operating characteristic (ROC) curves, Bland-Altman plots and intraclass correlation (ICC) were analysed for the ES:SEPS ratios.

RESULTS

The area under the curve (AUC) was decreased for the ES:SEPS ratios on the superior axial section through the vestibule (AUC 0.737) compared to the inferior axial (AUC 0.874) and sagittal sections (AUC 0.878). The resulting optimal thresholds (sensitivities/specificities) were 0.21 (0.66/0.75), 0.16 (0.77/0.9) and 0.285 (0.75/0.96). The reproducibility was excellent for all measures with ICCs of 0.97, 0.98 and 0.99.

CONCLUSION

Inferior axial or sagittal vestibular cross-sections are more accurate for the diagnosis of MD ears and have excellent reproducibility.

ADVANCES IN KNOWLEDGE

The choice of vestibular cross-section influences both the ability to distinguish MD from asymptomatic contralateral ears, and the optimum threshold ES:SEPS value.

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.

The "hype" of hydrops in classifying vestibular disorders: a narrative review

Background

Classifying and diagnosing peripheral vestibular disorders based on their symptoms is challenging due to possible symptom overlap or atypical clinical presentation. To improve the diagnostic trajectory, gadolinium-based contrast-enhanced magnetic resonance imaging of the inner ear is nowadays frequently used for the in vivo confirmation of endolymphatic hydrops in humans. However, hydrops is visualized in both healthy subjects and patients with vestibular disorders, which might make the clinical value of hydrops detection on MRI questionable.

Objective

To investigate the diagnostic value of clinical and radiological features, including the in vivo visualization of endolymphatic hydrops, for the classification and diagnosis of vestibular disorders.

Methods

A literature search was performed in February and March 2019 to estimate the prevalence of various features in healthy subjects and in common vestibular disorders to make a graphical comparison between healthy and abnormal.

Results

Of the features studied, hydrops was found to be a highly prevalent feature in Menière’s disease (99.4%). Though, hydrops has also a relatively high prevalence in patients with vestibular schwannoma (48.2%) and in healthy temporal bones (12.5%) as well. In patients diagnosed with (definite or probable) Menière’s disease, hydrops is less frequently diagnosed by magnetic resonance imaging compared to the histological confirmation (82.3% versus 99.4%). The mean prevalence of radiologically diagnosed hydrops was 31% in healthy subjects, 28.1% in patients with vestibular migraine, and 25.9% in patients with vestibular schwannoma. An interesting finding was an absolute difference in hydrops prevalence between the two diagnostic techniques (histology and radiology) of 25.2% in patients with Menière’s disease and 29% in patients with vestibular schwannoma.

Conclusions

Although the visualization of hydrops has a high diagnostic value in patients with definite Menière’s disease, it is important to appreciate the relatively high prevalence of hydrops in healthy populations and other vestibular disorders. Endolymphatic hydrops is not a pathognomic phenomenon, and detecting hydrops should not directly indicate a diagnosis of Menière’s disease. Both symptom-driven and hydrops-based classification systems have disadvantages. Therefore, it might be worth to explore features “beyond” hydrops. New analysis techniques, such as Radiomics, might play an essential role in (re)classifying vestibular disorders in the future.

Electronic supplementary material

The online version of this article (10.1007/s00415-020-10278-8) contains supplementary material, which is available to authorized users.

Endolymphatic hydrops magnetic resonance imaging in Ménière's disease

This review is designed to help radiologists interested in developing a magnetic resonance imaging service for patients with symptoms of Ménière's disease. Examples are selected from our experience with delayed post-gadolinium three-dimensional (3D) fluid attenuated inversion recovery (FLAIR) inner ear imaging of endolymphatic hydrops. The imaging features of the normal and hydropic endolymphatic structures, semiquantitative grading systems, normal variations, and differential diagnoses will be illustrated, whilst appropriate clinical referrals, approaches to reporting and diagnostic pitfalls will be discussed.

Early Magnetic Resonance Imaging for Patients With Idiopathic Sudden Sensorineural Hearing Loss in an Emergency Setting

OBJECTIVE

The role of magnetic resonance (MR) imaging in idiopathic sudden sensorineural hearing loss (ISSHL) is controversial due to the inhomogeneity of clinical and MR protocols. The aim of this work is to relate early MR findings obtained immediately after the admission, with the clinical presentation, the audiological findings, and the outcomes of treatment.

STUDY DESIGN

Prospective observational study.

SETTING

Tertiary referral university center.

PATIENTS

Forty-seven patients (22 M, 25 F; age: 54.4 ± 17.5 yr) consecutively referred to the Department of Emergency for ISSHL.

INTERVENTIONS

All patients underwent the diagnostic and therapeutic work-up for ISSHL, and MR imaging within 72 hours from the admission, independently of the symptoms onset. All patients received the same treatment (systemic steroid therapy, intratympanic steroid injection, and hyperbaric oxygen therapy).

MAIN OUTCOME MEASURE(S)

MR patterns, clinical, and laboratory findings.

RESULTS

MR imaging was positive in 25 of 47 cases (53%), with a perfect agreement between clinical and MR examinations (Cohen K = 1) upon the affected ear. Three different radiological patterns were observed: labyrinthine haemorrhage (n = 5), acute inflammatory process (n = 14), isolated blood-labyrinth barrier breakdown (n = 6). By binary logistic regression, only vertigo was associated with a positive MR imaging [B = 2.8; p = 0.011; OR = 9.5 (95% CI: 2.2-40.8)] and the latter was the only variable associated with an unfavorable outcome [(B = 2.8; p = 0.02 OR = 12.8 (95% CI: 2.9-56.7)].

CONCLUSION

Patients affected by ISSHL with associated vertigo show a higher likelihood of having a positive MR imaging, which, in turn, seems to predict an unfavorable outcome.

Three-Tesla magnetic resonance imaging of the vestibular endolymphatic space: A systematic qualitative description in healthy ears

BACKGROUND AND PURPOSE

A detailed knowledge of the normal Magnetic Resonance (MR) anatomy of the vestibular endolymphatic space (ES) could be useful to understand the linkage between endolymphatic hydrops (EH) and Ménière's disease (MD). Our aim was to describe the MR anatomy of the vestibular ES as depicted by MR imaging in healthy ears.

METHODS

This report describes a single-center retrospective study. Three readers analyzed the healthy ears of 22 consecutive patients who had undergone MRI for unilateral sudden hearing loss. The readers described the vestibular ES based on a delayed post-contrast 3D-FLAIR sequence according to six well-defined planes, three oblique sagittal (lateral, intermediate and medial) planes and three axial (superior, intermediate and inferior) planes.

RESULTS

On sagittal lateral and intermediate planes, we identified the SSC ampulla combined with the utricle in 22/22 ears. On the sagittal medial plane, the saccule was detectable in 15/22 (68%) ears, having a club shape with the long axis oriented cranio-caudally; in 7/22 (32%) ears, the saccule presented an oval/round shape that appeared more conspicuously on the axial intermediate plane. The ES occupied the half superior portion of the vestibule in 22/22 ears, never contacting the round and oval windows. On the axial plane, in 17/22 cases, the ES showed a Y-shaped arrangement, while in 5/22 ears (23%), the ES presented a more globular shape.

CONCLUSION

MR imaging represents a valid tool to explore the in vivo anatomy of the vestibular ES and to highlight its variability in normal ears.

MR Imaging in Menière Disease: Is the Contact between the Vestibular Endolymphatic Space and the Oval Window a Reliable Biomarker?

BACKGROUND AND PURPOSE

No reliable MR imaging marker for the diagnosis of Menière disease has been reported. Our aim was to investigate whether the obliteration of the inferior portion of the vestibule and the contact with the stapes footplate by the vestibular endolymphatic space are reliable MR imaging markers in the diagnosis of Menière disease.

MATERIALS AND METHODS

We retrospectively enrolled 49 patients, 24 affected by unilateral sudden hearing loss and 25 affected by definite Menière disease, who had undergone a 4-hour delayed 3D-FLAIR sequence. Two readers analyzed the MR images investigating whether the vestibular endolymphatic space bulged in the third inferior portion of the vestibule contacting the stapes footplate. This sign was defined as the vestibular endolymphatic space contacting the oval window.

RESULTS

We analyzed 98 ears: 27 affected by Menière disease, 24 affected by sudden sensorineural hearing loss, and 47 that were healthy. The vestibular endolymphatic space contacting the oval window showed an almost perfect interobserver agreement (Cohen κ = 0.87; 95% CI, 0.69-1). The vestibular endolymphatic space contacting oval window showed the following: sensitivity = 81%, specificity = 96%, positive predictive value = 88%, and negative predictive value = 93% in differentiating Menière disease ears from other ears. The vestibular endolymphatic space contacting the oval window showed the following: sensitivity = 81%, specificity = 96%, positive predictive value = 96%, negative predictive value = 82% in differentiating Menière disease ears from sudden sensorineural hearing loss ears.

CONCLUSIONS

The vestibular endolymphatic space contacting the oval window has high specificity and positive predictive value in differentiating Menière disease ears from other ears, thus resulting in a valid tool for ruling in Menière disease in patients with mimicking symptoms.